Enantioselective photo-organocatalytic intramolecular [2+2]-photocycloaddition of quinolones.
\r\n\tIn the book the theory and practice of microwave heating are discussed. The intended scope covers the results of recent research related to the generation, transmission and reception of microwave energy, its application in the field of organic and inorganic chemistry, physics of plasma processes, industrial microwave drying and sintering, as well as in medicine for therapeutic effects on internal organs and tissues of the human body and microbiology. Both theoretical and experimental studies are anticipated.
\r\n\r\n\tThe book aims to be of interest not only for specialists in the field of theory and practice of microwave heating but also for readers of non-specialists in the field of microwave technology and those who want to study in general terms the problem of interaction of the electromagnetic field with objects of living and nonliving nature.
",isbn:"978-1-83968-227-8",printIsbn:"978-1-83968-226-1",pdfIsbn:"978-1-83968-228-5",doi:null,price:0,priceEur:0,priceUsd:0,slug:null,numberOfPages:0,isOpenForSubmission:!1,hash:"8f6a41e4f5ce0e9c48628516d7c92050",bookSignature:"Prof. Gennadiy Churyumov",publishedDate:null,coverURL:"https://cdn.intechopen.com/books/images_new/10089.jpg",keywords:"Electromagnetic Wave, Microwave Energy Application, Electromagnetic Energy Generation, Intelligent Microwave Heating, Microwave Organic Chemistry, Microwave Reactor, Microwave Discharge, Microwave Plasma, Microwave Drying System, Tissue Microwave Heating, Measurement Automation, Industrial Microwave Process",numberOfDownloads:224,numberOfWosCitations:0,numberOfCrossrefCitations:0,numberOfDimensionsCitations:0,numberOfTotalCitations:0,isAvailableForWebshopOrdering:!0,dateEndFirstStepPublish:"July 3rd 2020",dateEndSecondStepPublish:"July 24th 2020",dateEndThirdStepPublish:"September 22nd 2020",dateEndFourthStepPublish:"December 11th 2020",dateEndFifthStepPublish:"February 9th 2021",remainingDaysToSecondStep:"7 months",secondStepPassed:!0,currentStepOfPublishingProcess:5,editedByType:null,kuFlag:!1,biosketch:"Prof. Gennadiy I. Churyumov is a professor at two universities: Kharkiv National University of Radio Electronics, and Harbin Institute of Technology and a senior IEEE member.",coeditorOneBiosketch:null,coeditorTwoBiosketch:null,coeditorThreeBiosketch:null,coeditorFourBiosketch:null,coeditorFiveBiosketch:null,editors:[{id:"216155",title:"Prof.",name:"Gennadiy",middleName:null,surname:"Churyumov",slug:"gennadiy-churyumov",fullName:"Gennadiy Churyumov",profilePictureURL:"https://mts.intechopen.com/storage/users/216155/images/system/216155.jfif",biography:"Gennadiy I. Churyumov (M’96–SM’00) received the Dipl.-Ing. degree in Electronics Engineering and his Ph.D. degree from the Kharkiv Institute of Radio Electronics, Kharkiv, Ukraine, in 1974 and 1981, respectively, as well as the D.Sc. degree from the Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine, Kharkiv, Ukraine, in 1997. \n\nHe is a professor at two universities: Kharkiv National University of Radio Electronics, and Harbin Institute of Technology. \n\nHe is currently the Head of a Microwave & Optoelectronics Lab at the Department of Electronics Engineering at the Kharkiv National University of Radio Electronics. \n\nHis general research interests lie in the area of 2-D and 3-D computer modeling of electron-wave processes in vacuum tubes (magnetrons and TWTs), simulation techniques of electromagnetic problems and nonlinear phenomena, as well as high-power microwaves, including electromagnetic compatibility and survivability. \n\nHis current activity concentrates on the practical aspects of the application of microwave technologies.",institutionString:"Kharkiv National University of Radio Electronics (NURE)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"2",totalChapterViews:"0",totalEditedBooks:"0",institution:null}],coeditorOne:null,coeditorTwo:null,coeditorThree:null,coeditorFour:null,coeditorFive:null,topics:[{id:"24",title:"Technology",slug:"technology"}],chapters:[{id:"74623",title:"Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures",slug:"influence-of-the-microwaves-on-the-sol-gel-syntheses-and-on-the-properties-of-the-resulting-oxide-na",totalDownloads:94,totalCrossrefCites:0,authors:[null]},{id:"75284",title:"Microwave-Assisted Extraction of Bioactive Compounds (Review)",slug:"microwave-assisted-extraction-of-bioactive-compounds-review",totalDownloads:12,totalCrossrefCites:0,authors:[null]},{id:"75087",title:"Experimental Investigation on the Effect of Microwave Heating on Rock Cracking and Their Mechanical Properties",slug:"experimental-investigation-on-the-effect-of-microwave-heating-on-rock-cracking-and-their-mechanical-",totalDownloads:28,totalCrossrefCites:0,authors:[null]},{id:"74338",title:"Microwave Synthesized Functional Dyes",slug:"microwave-synthesized-functional-dyes",totalDownloads:21,totalCrossrefCites:0,authors:[null]},{id:"74744",title:"Doping of Semiconductors at Nanoscale with Microwave Heating (Overview)",slug:"doping-of-semiconductors-at-nanoscale-with-microwave-heating-overview",totalDownloads:45,totalCrossrefCites:0,authors:[null]},{id:"74664",title:"Microwave-Assisted Solid Extraction from Natural Matrices",slug:"microwave-assisted-solid-extraction-from-natural-matrices",totalDownloads:25,totalCrossrefCites:0,authors:[null]}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"},personalPublishingAssistant:{id:"252211",firstName:"Sara",lastName:"Debeuc",middleName:null,title:"Ms.",imageUrl:"https://mts.intechopen.com/storage/users/252211/images/7239_n.png",email:"sara.d@intechopen.com",biography:"As an Author Service Manager my responsibilities include monitoring and facilitating all publishing activities for authors and editors. From chapter submission and review, to approval and revision, copyediting and design, until final publication, I work closely with authors and editors to ensure a simple and easy publishing process. I maintain constant and effective communication with authors, editors and reviewers, which allows for a level of personal support that enables contributors to fully commit and concentrate on the chapters they are writing, editing, or reviewing. I assist authors in the preparation of their full chapter submissions and track important deadlines and ensure they are met. I help to coordinate internal processes such as linguistic review, and monitor the technical aspects of the process. As an ASM I am also involved in the acquisition of editors. Whether that be identifying an exceptional author and proposing an editorship collaboration, or contacting researchers who would like the opportunity to work with IntechOpen, I establish and help manage author and editor acquisition and contact."}},relatedBooks:[{type:"book",id:"6826",title:"The Use of Technology in Sport",subtitle:"Emerging Challenges",isOpenForSubmission:!1,hash:"f17a3f9401ebfd1c9957c1b8f21c245b",slug:"the-use-of-technology-in-sport-emerging-challenges",bookSignature:"Daniel Almeida Marinho and Henrique Pereira Neiva",coverURL:"https://cdn.intechopen.com/books/images_new/6826.jpg",editedByType:"Edited by",editors:[{id:"177359",title:"Dr.",name:"Daniel Almeida",surname:"Marinho",slug:"daniel-almeida-marinho",fullName:"Daniel Almeida Marinho"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8494",title:"Gyroscopes",subtitle:"Principles and Applications",isOpenForSubmission:!1,hash:"cc0e172784cf5e7851b9722f3ecfbd8d",slug:"gyroscopes-principles-and-applications",bookSignature:"Xuye Zhuang and Lianqun Zhou",coverURL:"https://cdn.intechopen.com/books/images_new/8494.jpg",editedByType:"Edited by",editors:[{id:"69742",title:"Dr.",name:"Xuye",surname:"Zhuang",slug:"xuye-zhuang",fullName:"Xuye Zhuang"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8878",title:"Advances in Microfluidic Technologies for Energy and Environmental Applications",subtitle:null,isOpenForSubmission:!1,hash:"7026c645fea790b8d1ad5b555ded994d",slug:"advances-in-microfluidic-technologies-for-energy-and-environmental-applications",bookSignature:"Yong Ren",coverURL:"https://cdn.intechopen.com/books/images_new/8878.jpg",editedByType:"Edited by",editors:[{id:"177059",title:"Dr.",name:"Yong",surname:"Ren",slug:"yong-ren",fullName:"Yong Ren"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7714",title:"Emerging Micro",subtitle:"and Nanotechnologies",isOpenForSubmission:!1,hash:"5c6ea07211f78aafb0b53a184224d655",slug:"emerging-micro-and-nanotechnologies",bookSignature:"Ruby Srivastava",coverURL:"https://cdn.intechopen.com/books/images_new/7714.jpg",editedByType:"Edited by",editors:[{id:"185788",title:"Dr.",name:"Ruby",surname:"Srivastava",slug:"ruby-srivastava",fullName:"Ruby Srivastava"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10151",title:"Technology, Science and Culture",subtitle:"A Global Vision, Volume II",isOpenForSubmission:!1,hash:"1a9e7327c929421c873317ccfad2b799",slug:"technology-science-and-culture-a-global-vision-volume-ii",bookSignature:"Sergio Picazo-Vela and Luis Ricardo Hernández",coverURL:"https://cdn.intechopen.com/books/images_new/10151.jpg",editedByType:"Edited by",editors:[{id:"293960",title:"Dr.",name:"Sergio",surname:"Picazo-Vela",slug:"sergio-picazo-vela",fullName:"Sergio Picazo-Vela"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9336",title:"Technology, Science and Culture",subtitle:"A Global Vision",isOpenForSubmission:!1,hash:"e1895103eeec238cda200b75d6e143c8",slug:"technology-science-and-culture-a-global-vision",bookSignature:"Sergio Picazo-Vela and Luis Ricardo Hernández",coverURL:"https://cdn.intechopen.com/books/images_new/9336.jpg",editedByType:"Edited by",editors:[{id:"293960",title:"Dr.",name:"Sergio",surname:"Picazo-Vela",slug:"sergio-picazo-vela",fullName:"Sergio Picazo-Vela"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6516",title:"Metrology",subtitle:null,isOpenForSubmission:!1,hash:"09e6966a3d9fadcc90b1b723e30d81ca",slug:"metrology",bookSignature:"Anil",coverURL:"https://cdn.intechopen.com/books/images_new/6516.jpg",editedByType:"Edited by",editors:[{id:"190673",title:"Associate Prof.",name:"Anil",surname:"Akdogan",slug:"anil-akdogan",fullName:"Anil Akdogan"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1591",title:"Infrared Spectroscopy",subtitle:"Materials Science, Engineering and Technology",isOpenForSubmission:!1,hash:"99b4b7b71a8caeb693ed762b40b017f4",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",bookSignature:"Theophile Theophanides",coverURL:"https://cdn.intechopen.com/books/images_new/1591.jpg",editedByType:"Edited by",editors:[{id:"37194",title:"Dr.",name:"Theophanides",surname:"Theophile",slug:"theophanides-theophile",fullName:"Theophanides Theophile"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3092",title:"Anopheles mosquitoes",subtitle:"New insights into malaria vectors",isOpenForSubmission:!1,hash:"c9e622485316d5e296288bf24d2b0d64",slug:"anopheles-mosquitoes-new-insights-into-malaria-vectors",bookSignature:"Sylvie Manguin",coverURL:"https://cdn.intechopen.com/books/images_new/3092.jpg",editedByType:"Edited by",editors:[{id:"50017",title:"Prof.",name:"Sylvie",surname:"Manguin",slug:"sylvie-manguin",fullName:"Sylvie Manguin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3161",title:"Frontiers in Guided Wave Optics and Optoelectronics",subtitle:null,isOpenForSubmission:!1,hash:"deb44e9c99f82bbce1083abea743146c",slug:"frontiers-in-guided-wave-optics-and-optoelectronics",bookSignature:"Bishnu Pal",coverURL:"https://cdn.intechopen.com/books/images_new/3161.jpg",editedByType:"Edited by",editors:[{id:"4782",title:"Prof.",name:"Bishnu",surname:"Pal",slug:"bishnu-pal",fullName:"Bishnu Pal"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},chapter:{item:{type:"chapter",id:"52237",title:"Photo-Organocatalysis, Photo-Redox, and Electro- Organocatalysis Processes",doi:"10.5772/64633",slug:"photo-organocatalysis-photo-redox-and-electro-organocatalysis-processes",body:'\nIn general, organocatalysts are divided into two main classes according to the interaction, covalent or non-covalent (H-bonding, proton transfer, ion pair formation), with the organic substrate within the catalytic cycle. In this context, an organocatalyst reacts with an organic molecule in order to form a stable organic compound or a labile intermediate. At this stage, the activation induced by the organocatalyst enables the attack of the second reagent to form a second adduct that releases the desired product with the concomitant regeneration of the organocatalyst.
Most of the common organocatalysts used for carbon-carbon bond formation reactions are based in chiral and achiral secondary amines, while reagents are electrophiles such as aldehydes, ketones, or α,β-unsaturated carbonyls. For these cases, the selected organocatalysts normally promote the generation of either an iminium ion or an enamine. N-heterocyclic carbenes have also been used as organocatalysts that promote the polarity inversion of an organic moiety for C─C bond formation.
\nPhotocatalysis, where an electronically excited species acts as the catalyst, has gained increasing interest over the last years, with different organic transformations under such conditions being reported.
Recently, the catalytic activation of organic molecules by visible light photoredox catalysis that works under stereochemical control and provides chiral molecules in an asymmetric fashion has been largely reported. Generically, this approach relies on the ability of metal complexes and organic dyes to engage in single-electron transfer (SET) processes with organic substrates upon photoexcitation with visible light. Most common visible light photocatalysts are based on polypyridyl complexes of ruthenium, for example, tris(2,2′-bipyridine)ruthenium(II) or [Ru(bpy)3]2+, and iridium. These complexes absorb light in the visible region of the electromagnetic spectrum to give stable, long-living photoexcited states. The lifetime of the excited species is sufficiently long that it may engage in bimolecular electron transfer reactions in competition with deactivation pathways. Although these species are poor single-electron oxidants and reductants in the ground state, excitation of an electron affords excited states that are very potent single-electron transfer reagents. The ability of [Ru(bpy)3]2+ and related complexes to function as visible light photocatalysts has been recognized and currently applied to the electrolysis of water and the reduction in carbon dioxide to methane. These photocatalysts have also been employed in organic transformations including asymmetric approaches. Much of the excitement around visible light photoredox organocatalysis is due to the ability to achieve unique, if not exotic bond constructions that are not possible using the established protocols. For instance, photoredox organocatalysis can perform under overall redox neutral reactions where both oxidants and reductants are transiently generated in the same reaction vessel. This approach stands in contrast to methods requiring stoichiometric chemical oxidants and reductants, which are often incompatible with each other, as well as to electrochemical approaches, which are not amenable to redox neutral transformations.
\nElectro-organocatalysis has also received recent interest from both academia and industry. Electron transfer is one of the most important processes in organic chemistry in which one electron is added to or removed from an electroactive substrate. Such an electron transfer is reversible only when the resulting species are stable under those conditions. In other cases, an electron transfer generates subsequent chemical processes such as bond dissociation and bond formation. In general, radical cations and radical anions can be generated by electrochemical electron transfer reactions. Carbocations, carbon-free radicals, and carbanions can also be generated by subsequent bond dissociation or bond-forming processes. Several organic synthetic transformations especially carbon-carbon bond formation reactions, oxidation, and reduction processes (electrocatalytic processes) have been reported.
In the area of catalytic reactions, tremendous improvement has been made in the last decades, mostly upon the discovery of efficient transition metal catalysts. According to the variety of reactions, accessible, metal-catalyzed and enantioselective reactions have become significant tools in organic synthesis [1]. However, some disadvantages remain, such as the high cost and toxicity of the transition metal catalysts, employed and in some cases the problems that their residues, mainly in pharmaceutical products, can cause. Nonetheless, this transition metal catalysis will certainly continue to have an impact in synthetic organic chemistry in the future [2]. Alternatively, over the last years, a metal-free approach known as organocatalysis has reached a level of reliability that has allowed researchers to combine this procedure with other powerful techniques for molecule activation based on photochemical processes promoted by visible light. This green strategy has allowed previously unachievable synthetic issues to be solved and has rapidly progressed with application in both symmetric and asymmetric reactions (e.g., nucleophilic substitutions, Michael additions, cycloadditions, and aldol reactions) [3]. Generically, the organic catalysts can be categorized into two main classes according to the covalent or non-covalent (viz. H-bonding, proton transfer, ion pair formation) nature of the interaction established with the substrate within the catalytic cycle.
\nHomogeneous catalytic asymmetric transformations utilizing visible light photocatalysis include chiral and racemic photocatalysts with chiral organocatalysts, chiral Brønsted acids, or chiral Lewis acids [4]. In photo-organocatalytic processes, there are two main reaction models: the photocatalyst (PC) can act through an electron transfer (ET) process that causes an one-electron oxidation/reduction in the organic substrate R-X (Scheme 1, route a) or through hydrogen atom transfer (HAT, route b) from a hydrogen donor R-H [5]. Most of the photo-organocatalysts are aromatic ketones, dyes, and (chiral) secondary amines, while R substrates are electrophiles, typically aldehydes, ketones, or α,β-unsaturated carbonyls [5, 6]. Furthermore, photosensitization is known as an energy transfer between the excited photocatalyst (PC*) and substrate, which creates an excited state (R-Y*, from quenching of PC*), that is able to initiate a chemical reaction (route c). Sensitization can occurs by energy or electron transfer processes. The catalyst is transformed to act as a photosensitizer via photo-induced electron transfer (PET), hence leading the resulting photo-organocatalytic reaction to occur under stereoselective control [7].
\nNowadays, a possible alternative can be considered in the photochemical activation step, in which the complexation of an organic reagent R-Z is controlled by a distinct, photostable chiral catalyst (route d) [8].
\nThe aim of this subchapter was to point out the effective tools that the stereoselective ground-state processes offer to enantioselective photochemistry. The catalysts control the photoactivation of the substrates by inducing the transient formation of photon-absorbing chiral electron donor-acceptor (EDA) complexes. In addition, high stereocontrol in synthetically relevant intermolecular carbon-carbon bond-forming reactions driven by visible light can be provided by the inherent chirality of the catalysts.
\nThe group of Bach focuses on catalytic processes, which allow previously unknown transformations employing both photochemical and conventional techniques. Their published papers concern photoredox organocatalysis, such as the first highly enantioselective (up to 90% ee) singlet oxygen [2+4] cycloaddition reactions [9], but also some related with the photo-organocatalysis. In 2005, Bach and co-workers presented an enantioselective photo-induced electron transfer (PET) sensitization with significant turnover and high enantioselectivity [10]. These PET-catalyzed conjugate additions of α-amino alkyl radicals to enones have already been studied non-enantioselectively [11]. For the first time, an electron-accepting chiral organocatalyst was applied, in contrast to conventional complexing reagents. The (pyrrolidinylethyl) quinolone (PC1; 30 mol%) that induces a chiral environment on the substrate through hydrogen bonding at the bridgehead lactam, lead to the formation of the spirocyclic pyrrolizidine product in high enantiomeric excess and yields (ee up to 70%, yield 64%).
\nFour years later, the same group tested the intramolecular [2+2] photocycloaddition of prochiral 4-(3′-butenyloxy) quinolone to the desired products (Scheme 2) [12]. The previously characterized chiral organocatalyst-benzophenone PC1 indeed caused a rate acceleration of the photocycloaddition, but low stereoselectivity was achieved. In contrast, a novel synthesized xanthone PC2 proved to be a more active catalyst resulting in significant rate acceleration by triplet energy transfer and high enantiomeric excess values. After initial optimization using 20 mol% of chiral organocatalyst, it was possible to obtain the products in 94% ee (Table 1, entry 12). Bearing in mind these two catalysts as a potential prototype for synthetically relevant transformations of quinolones, in 2011 Bach and co-workers reported the synthesis of six 2-quinolones and their use in intramolecular [2+2] photocycloaddition [13].
\nThis photo-organocatalytic transformation was provided by applying a chiral, hydrogen-bonding template with an attached catalytically active sensitizing unit (benzophenone or xanthone). In all cases, it was possible to obtain high yields (78–99%) and enantioselectivities (83–94% ee) as shown in Table 1. These studies lead to a better understanding of stereoselective photo-organocatalytic processes, showing the importance of kinetic factors in creating an optimal catalytic cycle, as well as the activity range of different quinolones.
\nEntry | \nSubstrate | \nλ (nm) | \nCatalyst (mol%) | \nYield (%)a | \nee (%)b | \n
---|---|---|---|---|---|
1 | \n1 | \n300 | \n\nPC3 25 | \n43 | \n89 | \n
2 | \n2 | \n300 | \n\nPC3 25 | \n87 | \n>90 | \n
3 | \n3 | \n300 | \n\nPC3 25 | \n66 | \n83 | \n
4 | \n4 | \n366 | \n\nPC3 25 | \n89 | \n89 | \n
5 | \n5 | \n366 | \n\nPC3 25 | \n99 | \n90 | \n
6 | \n6 | \n366 | \n\nPC3 25 | \n99 | \n94 | \n
7 | \n4 | \n366 | \n\nPC2 10 | \n58 | \n92 | \n
8 | \n4 | \n366 | \n\nPC2 10 | \n75 | \n90 | \n
9 | \n4 | \n366 | \n\nPC2 10 | \n50 | \n91 | \n
10 | \n4 | \n366 | \n\nPC2 10 | \n46 | \n89 | \n
11 | \n4 | \n366 | \n\nPC2 5 | \n48 | \n90 | \n
12 | \n4 | \n366 | \nPC2 20 | \n53 | \n94 | \n
Enantioselective photo-organocatalytic intramolecular [2+2]-photocycloaddition of quinolones.
a Yield of isolated product.
b The enantiomeric excess of the straight photocycloaddition products was determined by chiral HPLC analysis.
In parallel, the group of Bach proposed an immobilization of earlier mentioned chiral photo-organocatalysts and their use in intramolecular [2+2] photocycloaddition of 4-allyloxyquinolone (Scheme 3) [14]. Under irradiation with light, the immobilized templates PC4 and PC5 allowed the substrate to undergo a [2+2] photocycloaddition to give the chiral products in high ee values and did not decrease even after the fourth use of recovered catalyst. Furthermore, the linking position of the catalyst at the C-6 carbon atom of the tetrahydronaphthalene was the one that rendered best results.
\nIn different experiments, the group of Bach also investigated enantioselective photochemical reactions resorting on chiral Lewis acids as catalysts [15]. They reported the AlBr3-activated chiral cationic oxazaborolidine catalyst for enantioselective intramolecular [2+2] photocycloaddition reactions of 4-alkenyl-substituted coumarins (78% ee were recorded with 20 mol% of catalyst). Nevertheless, the use of metals was inevitable.
\nMore recently, Vallavoju et al. [16] reported intramolecular [2+2] photocycloadditions of 4-alkenyl-substituted coumarins promoted by various atropisomeric binaphthyl-derived thioureas as photo-organocatalysts (Scheme 4). Thiourea catalysts are simple, environmentally benign, sustainable, and inexpensively synthesized from ‘chiral pool’, as well as easy to modulate and to handle. The photocatalytic cycle involves the formation of both static and dynamic complexes (exciplex formation) between the photo-organocatalyst and the reactive substrate, which are stabilized by hydrogen bonding. The corresponding products were achieved with high enantioselectivities (77–96% ee of product 1, Scheme 5) with low catalyst loading (1–10 mol%). The authors tested the catalyst readily prepared in one step from commercially available, optically pure 2-amino-2′-hydroxy-1,1′-binaphthalene with different functional groups, in order to understand the interaction(s) between the catalyst and improve the stereoselectivity. It was discovered that using catalyst PC6, an excellent conversion and high enantioselectivity of the photoproduct would be obtained (84% conversion; 74% ee of product 1). Nevertheless, the catalyst PC8 showed a great potential as photo-organocatalyst for this transformation resulting in 100% product conversion and 96% ee. Additionally, it was proved that reducing the PC8 catalyst loading from 100 to 30 to 10 mol% had a minimal impact on the enantioselectivity (94–96% ee; of product 1) of the photoaddition product, and the reaction was completed in 30 min. By controlling the reactivity of the excited state through the formation of static and dynamic complexes, photocatalysts or sensitizers with higher excited-state energies than the substrates can be completely avoided. This concept of catalysts may be a breakthrough in the discovery on new task-specific photo-organocatalysts.
\nMelchiorre and co-workers presented the catalytic approach using a chiral organic catalyst with hydrogen-bonding motifs to bind a specific substrate selectively in synthetically relevant intermolecular carbon-carbon bond-forming reactions driven by visible light [7]. In the asymmetric α-alkylation of aldehydes with alkyl halides, the commercially available diarylprolinol silyl ether catalysts [17] PC13 and PC14 were chosen due to their ability to induce high enantioselectivity in thermal reactions of aldehydes that carry on through enamine formation. The authors tested the possibility of EDA complex formation by addition of an excess of butanal (15 equiv.) and amines PC13 and PC14 (1 equiv.) in methyl tert-butyl ether (MTBE) with 2,4-dinitrobenzyl bromide (1 equiv.). Using either 2,6-lutidine or sodium acetate as bases, this model reaction provided the desired α-benzylated product with high enantioselectivity (Table 2, entries 1 and 2, 83% ee with PC14). In its turn, the chiral organocatalyst PC15 increased the ee value of the final product to 92%. The discovery of in situ created chiral EDA complexes from enamine intermediates which have the potential to participate actively in the photoexcitation of substrates without the required external photosensitizer, took the group of Melchiorre a step further.
\nIn 2014, the authors describe the first light-driven enantioselective organocatalytic alkylation of unmodified ketones with alkyl halides [18]. This correlates to the previously established mechanism, in which the chiral enamines are the key intermediates in ground-state organocatalytic asymmetric processes. A variety of chiral primary amines (20 mol%) to activate cyclohexanone towards benzylation with 2,4-dinitrobenzyl bromide were studied. A chiral secondary amine did not show any ability to catalyze the photochemical alkylation; nevertheless, the primary amines displayed promising (entries 4 and 5) or even excellent (entry 6) reactivity, but insufficient enantioselectivity. The primary cinchona-based amine catalyst PC16 confirmed the formation of photon-absorbing chiral electron donor-acceptor complexes, thus the photoactivation of the substrates. The benzylation product was obtained under cryogenic conditions (0°C) in a good yield and with an improved optical purity (60% yield, 90% ee, entry 7). Based on these optimized experiments, Melchiorre and co-workers examined different cyclic ketones in order to have an overview of the photochemical organocatalytic ketone alkylation approach. They discovered that a variety of N-Boc protected piperidine and dioxaspiro species can be readily active in this asymmetric alkylation reaction. Furthermore, the scope of the photochemical α-alkylation with diverse alkylating agents and cinchona-based amine catalyst led to the formation of α-alkylated products with high levels of regio-, diastereo-, and enantioselectivity.
\nAsymmetric α-alkylation of aldehydes and ketones with alkyl halides by photo-organocatalysis.
Last year, the group of Melchiorre reported the photo-organocatalytic enantioselective α- and γ-alkylation of aldehydes and enals with bromomalonates by a fluorescent light bulb without the need of any external photoredox catalyst [19]. The preliminary studies involved butanal and diethyl bromomalonate (Table 2) as substrates for this photo-organocatalytic reaction. The results showed that using the aminocatalyst PC14 (20 mol%) in a MTBE solution under irradiation, the alkylation product was obtained in high yield and enantioselectivity after 4 h (94% yield, 83% ee; entry 13). The detailed photochemical studies using absorption and emission spectroscopy suggested that the direct photoexcitation of the enamine could trigger the radical generation from diethyl bromomalonate. Furthermore, no photoabsorbing ground-state EDA complex formation was observed. Accordingly, the photochemical reaction proceeds through a different mechanism. As previously described, the metal-free process depends on the creation of photon-absorbing electron donor-acceptor (EDA) complexes [18], generated in the ground state upon association of electron-deficient benzyl and phenacyl bromides II with the electron-rich enamine I (Scheme 5A). A single-electron transfer (SET) induced by visible light irradiation of the colored EDA complex III allows access to radical species under mild conditions. This reactivity allowed the expansion of a light-driven stereoselective α-alkylation of carbonyl compounds [18]. In contrast to this, the authors suggest a novel photo-organocatalytic mechanism, in which enamines can use to drive the photochemical generation of radicals acting as a photosensitizer upon direct photoexcitation (Scheme 5B). The enamine I, under light absorption, reaches an electronically excited state (I*) and to act as a photoinitiator causing the formation of the electron-deficient radical V through the reductive cleavage of the bromomalonate C─Br bond via a single-electron transfer (SET) mechanism (Scheme 5B) [19, 20]. Taking into consideration the capacity of I to infer high stereoselectivity in enamine-mediated polar reactions, adding the radical V to the ground-state I progresses in a stereocontrolled manner. Since α-aminoalkyl radicals known as strong reducing agents, the intermediate VI would induce the reductive cleavage of bromomalonate through an outersphere SET process, thus regenerating the radical V. This route affords a bromide iminium ion pair VII, which then hydrolyzes to release the desired product and the aminocatalyst PC14. Then, the scope of enantioselective organocatalytic alkylation of aldehydes and enals was examinated. Differently substituted bromomalonates successfully contributed to the enantioselective alkylation of butanal at room temperature (Table 2, entry 14). Aldehydes with a heteroatom moiety, long-alkyl chain, or an internal olefin, were also stereoselectively alkylated to give products with good enantioselectivity (Table 2, entry 15). Additionally, it was presented that enamine intermediates, synthesized from α-branched enals, could trap the generated radical while locating a new stereocenter at a distant γ-position.
\nIn parallel, the same group of researchers investigated the phase transfer catalyzed, enantioselective perfluoroalkylation and trifluoromethylation of cyclic β-ketoesters under visible light irradiation [21]. The photo-organocatalytic approach is again caused by the photochemical activity of EDA complexes generated in situ from the ground-state association of chiral enolates and perfluoroalkyl iodides. Irradiating the colored EDA complex induces a single-electron transfer (SET) allowing access to radical species at ambient temperature. Perfluoroalkyl iodides were selected as electrophiles due to their potential for facilitating EDA associations in the ground state. At the same time, chiral quaternary ammonium salts were used as phase transfer catalysts (PTC) that enabled the formation of a chiral ion pair after deprotonation of β-ketoesters by an inorganic base [22]. Perfluoroalkylation of one indanone methyl ester with perfluorohexyl iodide in chlorobenzene under visible light irradiation with PTC organocatalyst was chosen as model reaction. The best results were obtained using the pseudo-enantiomeric cinchonine PC20 derivative catalysts, with an excess of perfluorohexyl iodide (3 equiv) for 64 h (59% yield, 93% ee) (Scheme 6) [21].
\nThe above presented strategies of enantioselective photo-organocatalytic processes have a great potential for the sustainable preparation of chiral molecules, a rapidly developing area of modern chemical research.
\nIn parallel to the efforts performed in the field of asymmetric photo-organocatalysis, some attempts were also performed in the non-enantioselective processes.
\nNon-asymmetric photocatalysis has gained a great deal of attention during the last decades [23, 24], and a remarkable and interesting case was recently described by the already cited group of Melchiorre, in which an aromatic aldehyde was involved in the intermolecular atom transfer radical additions (ATRA) of a variety of haloalkanes to alkenes, one of the essential carbon-carbon bond-forming processes in organic chemistry [25]. In an ATRA reaction, the addition of an organic halide across a carbon-carbon double-bond yields a new C─C and C─X bond (X = halogen) in a single operation. Once more, organic compounds known to be capable of high photoreactivity [25] could alternatively be used as an energy transfer photocatalyst. It is important to note that for the first time, aromatic aldehydes have been used as photo-organocatalysts in an effective and valuable process [26]. Recent exciting findings by Melchiorre and co-workers have also shown the metal-free photo-organocatalysis which allows the direct alkylation of 2- and 3-substituted 1H-indoles with electron-accepting benzyl and phenacyl bromides [27].
\nThe term photoredox organocatalysis has its origin in the work by Nicewicz and MacMillan in 2008. They reported the enantioselective α-alkylation of aldehydes using [Ru(bpy)3]Cl2 as a photoredox catalyst. This complex, alongside many others such as [Ir(ppy)2(dtb-bpy)]PF6 and fac-[Ir(ppy)3] that have been subsequently reported, acts as strong oxidizers in the excited state upon absorbing visible light. In general, different inorganic solid photocatalysts such as TiO2 and ZnO have been largely explored as photoredox catalysts. The poor absorption of visible light by such inorganic photocatalysts is considered a limitation for application in organic synthetic processes using solar energies. In contrast, organic photocatalysts show some advantages regarding their low-cost, significant synthetic versatility, and the possibility to tune their redox properties. In this context, the organic photoredox dyes are usually selected according to their λmax and redox potential E0.
\n\nScheme 7 depicts the most popular dyes investigated in photoredox catalysis procedures.
\nThe photoactivation reveals the ability of the photosensitizer to absorb in the visible domain and to act both as a strong oxidant in the excited state S* and as an efficient reductant in its semi-reduced form S•–. In Scheme 8, a comparison between the general photoredox catalytic cycles of ruthenium-based catalysts and a photo-organocatalyst, viz. Eosin Y (EY), is presented.
\nOne of the most explored aspects investigated in the field of enantioselective photoredox catalysis has been the use of organic dyes as photocatalysts. In the seminal work by Zeitler et al. [28], they reported the efficient cooperative asymmetric intermolecular α-alkylation of aldehydes catalyzed by Eosin Y under LED green light and in the presence of MacMillan’s imidazolidinone catalyst A (see Scheme 9 for a simplified proposed mechanism of the reaction). According to the electron-withdrawing groups of the substrates [diethylmalonate, p-nitrophenyl (PNP) and polyfluorinated alkane], the reactions performed better between −15 and +5°C with yields from 56 to 85% and enantiomeric excesses higher than 86%, despite the 18 h reaction time (see Table 3, entries 1–4).
\nUsing the same conditions adapted to a microreactor flow regime, smaller reaction times were obtained with comparable results [29]. Rose Bengal was also applied as photoredox catalyst in this type of reaction (Table 3, entries 3–9). Again, imidazolinone A was employed as well as a Lewis acid such as LiCl to co-catalyze the photoreaction [30].
\nOn the other hand, asymmetric α-amination of aldehydes has also been accomplished by means of photoredox chemistry [31]. By using an amine substrate bearing ODNs, photolabile groups that simultaneously work as the photoredox catalyst and also release the reactive carbamyl reagent that couples with the in situ formed enamines; sixteen α-amino aldehydes were successfully prepared in 67–79% yield and >86% ee (see Table 4).
\n\x3c!--Entry | \nR1 | \nR2 | \nR3 | \nYield (%) | \nee (%) | \nRef. | \n
---|---|---|---|---|---|---|
1 | \nn-Pentane | \nH | \n(CF2)3CF3 | \n56 | \n96 | \n[28] | \n
2 | \nn-Pentane | \nH | \nPNP-CO | \n82 | \n95 | \n[28] | \n
3 | \nPh | \nCO2Et | \nH | \n76 | \n86 | \n[28] | \n
\n | Ph | \nCO2Et | \nH | \n89 | \n83 | \n[30] | \n
4 | \nn-Pentane | \nCO2Et | \nH | \n85 | \n88 | \n[28] | \n
\n | n-Pentane | \nCO2Et | \nH | \n88 | \n80 | \n[30] | \n
5 | \n4-tBuPh | \nCO2Et | \nH | \n51 | \n83 | \n[30] | \n
6 | \n3-ClPh | \nCO2Et | \nH | \n90 | \n82 | \n[30] | \n
7 | \n4-OMePh | \nCO2Et | \nH | \n94 | \n80 | \n[30] | \n
8 | \n2,4-(OMe)2Ph | \nCO2Et | \nH | \n51 | \n83 | \n[30] | \n
9 | \n(CH2)2CH═CHEt | \nCO2Et | \nH | \n56 | \n85 | \n[30] | \n
Asymmetric alkylation of aldehydes catalyzed by Eosin Y or Rose Bengal.
Entry | \nR1 | \nR2 | \nR3 | \nYield (%) | \nee (%) | \nRef. | \n|
---|---|---|---|---|---|---|---|
1 | \nPh | \nMe | \nCbz | \n77 | \n89 | \n[31] | \n\n |
2 | \nPh | \nMe | \nAlloc | \n75 | \n90 | \n[31] | \n|
3 | \nPh | \nMe | \nBoc | \n71 | \n89 | \n[31] | \n|
4 | \nPh | \nMe | \nFmoc | \n73 | \n89 | \n[31] | \n|
5 | \nPh | \nBu | \nCO2Me | \n76 | \n90 | \n[31] | \n|
6 | \nPh | \nMOM | \nCO2Me | \n75 | \n94 | \n[31] | \n|
7 | \nPh | \n(CH2)3Ph | \nCO2Me | \n71 | \n86 | \n[31] | \n|
8 | \nPh | \nMe | \nCO2Me | \n79 | \n92 | \n[31] | \n|
9 | \n\nn-pent | \nMe | \nCO2Me | \n71 | \n90 | \n[31] | \n|
10 | \n(CH2)2OBn | \nMe | \nCO2Me | \n73 | \n88 | \n[31] | \n|
11 | \n(CH2)2ONPhth | \nMe | \nCO2Me | \n77 | \n90 | \n[31] | \n|
12 | \nCH═CH2 | \nMe | \nCO2Me | \n76 | \n90 | \n[31] | \n|
13 | \n(CH2)2CO2Et | \nMe | \nCO2Me | \n71 | \n90 | \n[31] | \n|
14 | \nPMP | \nMe | \nCO2Me | \n79 | \n91 | \n[31] | \n|
15 | \nCyclohexyl | \nMe | \nCO2Me | \n72 | \n91 | \n[31] | \n|
16 | \nMe2 | \nMe | \nCO2Me | \n67 | \n94 | \n[31] | \n
Asymmetric α-amination of aldehydes by ODNs dual catalysis.
Entry | \nR1 | \nR2 | \nYield (%) | \nee(%) | \nRef. | \n|
---|---|---|---|---|---|---|
1 | \n4-FPh | \niPr | \n72 | \n83 | \n[32] | \n|
2 | \nPh | \niPr | \n75 | \n97 | \n[32] | \n|
3 | \nPh | \n(CH2)2SCH3 | \n76 | \n69 | \n[32] | \n\n |
4 | \nPh | \nBn | \n37 | \n88 | \n[32] | \n
Decarboxylative reduction in 1-aryl-2,2,2-trifluoroethyl-substituted amino acids.
Cyclization of polyprenoids and 1,3-ketocabonyls catalyzed by Eosin Y.
Wallentin et al. [32] reported the photocatalyzed decarboxylative reduction in several classes of biologically relevant enantio-enriched 1-aryl-2,2,2-trifluoroethyl-substituted amino acids (see Table 5). A plausible redox-coupled hydrogen shuttle mechanism was proposed by using one of the strongest oxidizing organic dyes mesityl acridinium (Mes-Acr+BF4−, E1/2red = +2.06 V vs SCE) as photoredox catalyst and bis(4-chlorophenyl)disulphide (DDDS) as a sacrificial hydrogen atom donor. This methodology was also applied to the synthesis of other achiral carboxylic acids, namely α-amino acids, α-hydroxy acids, and phenylacetic acids in moderate to quantitative yields.
\nA stereoselective radical cascade cyclization of polyprenoids through a photocatalytic mechanism has been reported yielding polyenes in moderate to very high yields with excellent diastereoselectivities (d.r. > 19:1) in HFIP and using Eosin Y as the photoredox catalyst (Table 6) [33]. The methodology was based on the cyclization by terminal OH groups of a large substrate array of aliphatic alcohols, phenols, or enols, which was tolerable to electron-rich or electron-poor substituents. In addition, the cyclization of 1,3-diketones required the use of LiBr as a weak Lewis acid. Stern-Volmer analysis reinforced that these reactions proceeded via a PET-induced radical mechanism.
\nThe photoredox catalyst 2,4,6-tris(4-methoxyphenyl)pyrylium tetrafluoroborate (D) was used in the enantioselective ring opening metathesis polymerization (ROMP) of endo-DCPD to provide the corresponding linear polymer with conversion yields as high as 20% [34] (Scheme 10). The copolymerization of this monomer with norbornene was also accomplished. By using partially hydrogenated monomers, side reactions at the terminal positions were hindered which enabled higher degrees of polymerization to be obtained. By applying visible light, the polymerization can be turned on or off at will, bringing a dynamic nature to it by exposure to the stimulus.
\nOver the last years, several publications involving non-asymmetric photoredox organocatalytic synthetic transformations mediated by metal-free organic photoredox catalysis under mild conditions have been reported [35].
\nFrom the industrial point of view, it is important to focus the recent developments on selective photocatalytic transformations of benzene, in particular the oxidation of benzene to phenol [36], alkoxylation of benzene [37], and monofluorination of benzene with fluoride and oxygen [38]. As an alternative to inorganic catalysts, the selective oxidation of benzene to phenol can be made under visible light irradiation of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in an oxygen-saturated acetonitrile solution of benzene and water [39]. In 2004, Fukuzumi et al. [40] reported the use of 9-mesityl-10-methylacridinium (Acr+-Mes) ion as an efficient photoredox catalyst due to its high oxidizing and reducing abilities of the long-lived electron transfer (ET) state. Acr+-Mes provides an efficient mediator to the formation of radical cations of electron donors and radical anions of electron acceptors thus enabling coupling between electron donors and acceptors.
\nPhotocatalytic [2+2] cycloaddition of dioxygen to tetraphenylethylene (TPE) via electron transfer reactions of TPE and oxygen with the ET state of Acr+-Mes is one example of the strategies described before [41].
\nEosin Y as a well-known low-cost organic dye that absorbs green light (characteristic peak at 539 nm) has been extensively investigated as photoredox catalyst for different organic transformations [42–49].
\nAs described in the previous sections, the electron transfer (ET) process is a crucial step in the organic chemistry field on which many organic reactions rely in order to occur [50, 51]. Essentially, an electron transfer process is based on the removal (or addition) of at least one electron from (or to) the electroactive substrate. This process is considered reversible only when the obtained products are stable under those experimental conditions. An electron transfer can generate intermediates which subsequently undergo chemical processes such as bond dissociation and bond formation. Basically, electroctrochemical techniques can be applied to establish the electrochemical oxidation and reduction mechanisms, that is the electron transfer reaction (formation and determination of the intermediates) and subsequent chemical reaction associated with the electrochemical generated process (formation of the reaction products). Thus, those formed intermediates are radical cations (or radical anions), and they can be generated by electrosynthetic processes using organic compounds. Carbon-free radicals (carbocations and carbanions) can also be generated by subsequent bond dissociation or bond formation process. Several electro-organic synthetic transformations, especially carbon-carbon, carbon-nitrogen, and carbon-phosphorous bond formation reactions, as well as oxidation and reduction processes have been reported [52]. Electrochemical processes are considered ‘green’ procedures for those synthetic transformations. The main advantage of the electrosynthetic approach is that electrons flow as current and are regard as one inexpensive reactant, thus making the route more environmentally friendly. Moreover, reactions take place in low-temperature conditions, reducing the local consumption of energy and the risk of corrosion, material failure, and accidental release. Finally, it is important to highlight that electrodes can be regarded as heterogeneous catalysts that are easily separated from the products. The low or even almost inexistent volatility of the reaction media is another factor to be taken into account. Therefore, electro-organocatalysis constitutes a valuable tool for the organic chemist with numerous applications in both academia [53, 54] and industry [55].
\nThe electro-organocatalysis field can be divided into two main branches, depicted in Scheme 11(A) direct electrolysis, in which the redox process occurs between the electrode surface and the reactant without the addition of other compounds and (B) ‘indirect electrolysis’ where the redox process occurs between the electrode surface and an external redox catalyst (or ‘mediator’) which then performs the ET with the reactive species) [56].
\nIn the direct electro-organocatalysis process, the electron transfer (ET) step occurs at the electrode surface. Due to its heterogeneous nature, the catalyst recycling can be performed easily by separating it from the reaction media after the formation of the desired organic product.
\n\'Direct electro-organocatalysis\' or electro-organic synthesis has recently gained increasing attention, which can be attributed to their sustainable and ‘green’ features when compared to the traditional ones.
\nIn the literature, there are few reports concerning bond formation and bond dissociation reactions. Gallardo and co-workers reported the formation of C─C [52, 57, 58], C─N [58], C─P [59], and C─S [60] bonds by an electrochemical approach of nucleophilic aromatic substitution reactions (SNAr). The proposed new route for the electrochemical processes consists on the reaction between an electron-deficient, aromatic compound and a nucleophile, leading to the formation of a σ-complex or Meisenheimer complex intermediate. Then, this species undergoes an oxidation that leads to the departure of the leaving group (heteroatom radical [NASX] and/or hydride, two electrons and a proton [NASH]). This procedure was similarly conducted with other nucleophiles (hydride, cyanide, fluoride, methoxy, ethanethiolate, and n-butylamine) and aromatic compounds as starting materials. In addition, preparative electrolysis was also employed as means to promote the oxidation of the intermediate produced in the first step of the process [52, 58].
\nThis technique allows determination, characterization, and quantification of the type and number of electrochemically produced complexes present in the reaction media. It is also possible to assess if the reaction was successful once most classical SNAr reactions give lower yields.
\nThe main drawbacks of the electrochemical approach are the use of solvent and the amount of tetraalkylammonium salt as electrolyte, which consequently have to be separated from the desired product. The use of ionic liquids (ILs) in particular room temperature ionic liquid (RTIL) as solvents may address this specific problem. They are considered non-flammable, non-volatile, and thermally stable over a wide range of temperatures, as well as good solvents for organic and inorganic compounds. In addition, they may be applied concomitantly as solvent and as electrolyte thereby enhancing the ‘green’ aspect of these procedures.
\nGallardo and co-workers [61] adapted the electrochemical approach of nucleophilic aromatic substitution reactions to this \'greener\' alternative family of solvents. The authors described the investigation of the electrocatalytic process as well as regioselectivity effects induced by the solvation properties of the RTILs (1-butyl-3-methylimidazolium [BMIM] combined with tetrafluoroborate [BF4], hexafluorophosphate [PF6], bis(trifluoromethylsulfonyl)imide [NTf2], and acetate [AcO] as anions).
\nThe use of electrochemical techniques such as cyclic voltammetry (CV) and controlled potential electrolysis allows the evaluation of the nature and stability of the electrochemically generated intermediate on the solvent, as well as the extension of the reaction.
\nDespite the successful reports on SNAr reactions, the ‘direct electrolysis’ approach requires the application of high potentials in order for the electrosynthetic process to occur. To address this issue, the redox process can be applied to organocatalysts which then lead to yield the desired products in the indirect electrocatalysis fashion.
\nIn the indirect electro-organocatalysis process, the electron transfer (ET) step is shifted from a heterogeneous process occurring at the electrode surface (as described earlier as ‘direct electrolysis’) to homogeneous process that can provide an electrochemically generated substance which acts as a so-called organocatalyst (or ‘mediator’). Usually triarylamines, triarylimidazoles and N-oxyl radicals [62] are employed as these electroauxiliary species. The group of R. D. Little has reported several environmentally friendly methodologies to obtain products via \'indirect electro-organocatalysis\' in which no metal catalyst and external chemical oxidants were employed [63–65].
\nIn order to explore and generalize this methodology, analogous organocatalysts with modified aromatic rings were also reported by the authors. The desired products were formed in good yields [63].
\nIn this specific case of the ‘indirect electro-organocatalysis’, particular conditions of solvent and catalyst are employed in order to enhance the enantioselectivity of the formed products. It is considered as safer and ‘green route’ towards enantioselective reactions by combining asymmetric organocatalysis with electrochemistry. The selected organocatalysts are stable, stereoselective organic compounds that can undergo the electrosynthetic process under unsuitable conditions for conventional catalysts. Asymmetric electro-organocatalysis methodologies have been successfully employed to produce several optically active compounds with application in life sciences. Scheme 12 depicts the direct intermolecular α-arylation of aldehydes to produce meta-alkylated anilines using electron-rich aromatic compounds [66].
\nThe described methodology for the regio- and stereoselective electroorganocatalyzed production of the meta-substituted anilines takes place in two steps: (1) firstly occurs the electrochemical activation of the aromatic compound that evolves to an electrophilic intermediate and (2) then an electron-rich enamine is generated by the condensation of the organocatalyst and the desired aldehyde, which subsequently undergoes a nucleophilic addition to the intermediate formed in step 1, giving rise to another intermediate that upon hydrolysis and proton transfer regenerates the organocatalyst and yields the corresponding product. The described reactions occur between the tosyl-protected reactant with a series of aldehydes catalyzed by [(S)-2-[diphenyl(trimethylsilyloxy)methyl]pyrrolidine] (PC13), which has also been reported for the photocatalyzed α-alkylation of aldehydes [7]. In these conditions, the meta-substituted aniline enantiomeric products were obtained in 54–75% yields and high enantiomeric excess between 81 and 96% (Scheme 13) [66].
\nIn 2005, Schäfer and co-workers [67] reported the reaction of enamines and mediated anodic oxidation of carbohydrates in the presence of 2,2,6,6-tetramethylpiperidine-1-oxoammonium cation ([TEMPO]) as organocatalyst. These species reacted with selected enaminoesters to form intermediate imidazolium cations, which selectively oxidize the primary hydroxy groups of trisaccharides at the anode to give tricarboxylic acid sugars in 50–80% yields. The relative stability of the electrogenerated TEMPO cation in acetonitrile enables it to react as a selective oxidant, electrophile, and also catalyst.
\nEnantioselective α-oxyamination of aldehydes has been reported by the group of H.-J. Jang using a sec-amine as chiral catalyst (Scheme 14) [68]. An enamine intermediate is formed by anodic oxidation of the aldehydes that ultimately reacts with TEMPO leading to the formation of the desired products in reasonable yields. Once again using PC13 as organocatalyst, α-oxyaldehydes were obtained in 23–57% yields and 60–70% ee.
\nAn asymmetric electro-organocatalysis method for enantioselective α-alkylation of aldehydes with xanthene has also been devised by the group of Jang et al. [69]. Scheme 15 depicts the best results using a chiral imidazole as organocatalyst, which was chosen from a plethora of differently substituted imidazole-based compounds [69]. According to electrochemical studies and control experiments, the reaction is probable to occur through the formation of an enamine intermediate. DFT calculations suggested that xanthene adds to the opposite side of the phenyl ring of the radical intermediate blue to stereochemical hindrance issues, thus enhancing the stereoselectivity of the reaction.
\nIn 2014, Xu and co-workers [70] published an electrochemical intramolecular aminooxygenation reaction of unactivated alkenes based on the addition of N-centered radicals to alkenes (generated from electrochemical oxidation) followed by trapping of the cyclized radical intermediate with TEMPO. This process allowed the preparation of different aminooxygenation products in high yields and excellent trans-selectivity for cyclic systems (d.r. up to > 20:1).
\nVery recent, Xu and collaborators [71] reported the first electrocatalytic method using ferrocene as a cheap redox catalyst to produce amidyl radicals from N-arylamides. The conventional methods for oxidative generation of amidyl radicals from N─H amides need to use a stoichiometric quantity of expensive noble-metal catalysts or strong oxidants. In this case, the authors showed an efficient radical-generating process based on intramolecular olefin hydroamidation reaction.
\nThis work was supported by Fundação para a Ciência e a Tecnologia through projects (PEst-C/LA0006/2013) one contract under principal investigator FCT (L.C. Branco) and one postdoctoral fellowships (Hugo Cruz—SFRH/BPD/102705/2014).
Voltammetry is an electrochemical technique for current-voltage curves, from which electrode reactions at electrode-solution interfaces can be interpreted. Since current-voltage curves, called voltammograms, include sensitive properties of solution compositions and electrode materials, their analysis provides not only chemical structures and reaction mechanisms on a scientific basis but also electrochemical manufacture on an industrial basis. The voltammograms vary largely with measurement time except for steady-state measurements, and so it is important to pay attention to time variables. Voltage is a controlling variable in conventional voltammetry, and the current is a measured one detected as a function of applied voltage at a given time.
\nThe equipment for voltammetry is composed of electrodes, solution, and electric instruments for voltage control. Electrodes and electric instruments are keys of voltammetry. Three kinds of electrodes are desired to be prepared: a working electrode, a counter one, and a reference one. The three will be addressed below.
\nLet us consider a simple experiment in which two electrodes are inserted into a salt-included aqueous solution. When a constant current is applied to the two electrodes, reaction 2H+ + 2e− → H2 may occur at one electrode, and reaction 2OH− → H2O2 + 2e− occurs at the other. The current is the time variation of the electric charge, and hence it is a kind of reaction rate at the electrode. Since the applied current is a sum of the two reaction rates, one being in the positive direction and the other being in the negative, it cannot be attributed to either reaction rate. A technique of attributing the reactions is to use an electrode with such large area that an uninteresting reaction rate may not become a rate-determining step. This electrode is called a counter electrode. The current density at the counter electrode does not specifically represent any reaction rate. In contrast, the current density at the electrode with a small area stands for the interesting reaction rate. This electrode is called a working electrode. It is the potential difference, i.e., voltage, at the working electrode and in the solution that brings about the electrode reaction. However, the potential in the solution cannot be controlled with the working electrode or the counter one. The control can be made by mounting another electrode, called a reference electrode, which keeps the voltage between an electrode and a solution to be constant. However, the constant value cannot be measured because of the difference in phases. A conventionally employed reference electrode is silver-silver chloride (Ag-AgCl) in high concentrated KCl aqueous solution.
\nAn electric instrument of operating the three electrodes is a potentiostat. It has three electric terminals: one being a voltage follower for the reference electrode without current, the second being a current feeder at the counter electrode, and the third being at the working electrode through which the current is converted to a voltage for monitoring. A controlled voltage is applied between the working electrode and the reference one. These functionalities can readily be attained with combinations of operational amplifiers. A drawback of usage of operational amplifiers is a delay of responses, which restricts current responses to the order of milliseconds or 10 kHz frequency.
\nVoltammetry includes various types—linear sweep, cyclic, square wave, stripping, alternating current (AC), pulse, steady-state microelectrode, and hydrodynamic voltammetry—depending on a mode of the potential control. The most frequently used technique is cyclic voltammetry (CV) on a time scale of seconds. In contrast, currently used voltammetry at time as short as milliseconds is AC voltammetry. We describe here the theory and tips for practical use of mainly the two types of voltammetry.
\nThe theory of voltammetry is to obtain expressions for voltammograms on a given time scale or for those at a given voltage. First of all, it is necessary to specify rate-determining steps of voltammograms. There are three types of rate-determining steps under the conventional conditions: diffusion of redox species in solution near an electrode, adsorption on an electrode, and charging processes at the double layer (DL). Electric field-driven mass transport, called electric migration, belongs to rare experimental conditions, and hence it is excluded in this review. When a redox species in solution is consumed or generated at an electrode, it is supplied to or departed from the electrode by diffusion unless solution is stirred. When it is accumulated on the electrode, the change in the accumulated charge by the redox reaction provides the current. Whenever electrode voltage is varied with the time, the charging or discharging of the DL capacitor causes current. Therefore, the three steps are frequently involved in electrochemical measurements.
\nA mass transport problem on voltammetry is briefly described here. The redox species is assumed to be transported by one-directional (x) diffusion owing to heterogeneous electrode reactions. Then, the flux is given by f = −D(∂c/∂x), where c and D are the concentration and the diffusion coefficient of the redox species, respectively. Redox species in solution causes some kinds of chemical reaction through chemical reaction rates, h(c, t). Then the reaction rate is the sum of the diffusional flux and the chemical reaction rate, ∂c/∂t = −∂f/∂x − h(c, t). Here the equation for h = 0 is called an equation of continuum. Eliminating f with the above equation on the assumption of a constant value of D yields ∂c/∂t = D(∂2c/∂x2) − h(c, t). This is an equation for diffusion-chemical kinetics. The expression at h = 0 is the diffusion equation. A boundary condition with electrochemical significance is the control of c at the electrode surface with a given electrode potential. If the redox reaction occurs in equilibrium with the one-electron transfer at the electrode, the Nernst equation for the concentrations of the oxidized species, co, and the reduced one, cr, holds.
\nwhere Eo is the formal potential. If there is no adsorption, the zero-flux condition in the absence of accumulation is valid:
\nThe other conditions are concentrations in the bulk (x → ∝) and the initial conditions.
\nIf the mass transport is controlled only by x-directional diffusion, cr and co are given by the diffusion equations, ∂c/∂t = D(∂2c/∂t2) for c = cr or co. An electrochemically significant quantity is not concentration in any x and t, but a relation between the surface concentrations and the current (the flux at x = 0). On the assumption of Do = Dr = D, of the initial and boundary conditions, (cr)t = 0 = c*, (co)t = 0 = 0, and (cr)x = ∞ = c*, (co)x = ∞ = 0, a solution of the initial-boundary problem is given by [1].
\nwhere j is the current density. The common value of the diffusion coefficients yields co + cr = c* for any x and t. Inserting this relation and Eq. (3) into the Nernst equation, (co)x = 0 = c*/[1 + exp[−F(E − Eo)/RT]], we obtain the integral equation for j as a function of t or E.
\nWhen the voltage is linearly swept with the time at a given voltage scan rate, v, from the initial potential Ein, Eq. (3) through the combination with the Nernst equation becomes
\nThe above Abel’s integral equation can be solved by Laplace transformation. When the time variation is altered to the voltage variation through E = Ein + vt, the current density is expressed as
\nwhere ζ = (E − Eo)F/RT and ζi = (Ein − Eo)F/RT. Evaluation of the integral has to resort to numerical computation. Current at any voltage should be proportional to v1/2, as can be seen in Eq. (5). The voltammogram for v > 0 rises up from Eo, takes a peak, and then deceases gradually with the voltage. The decrease in the current is obviously ascribed to relaxation by diffusion. The peak current density is expressed by
\nat Ep = Eo + 0.029 V at 25°C, where 0.446 comes from the numerical calculation of the integral of Eq. (5).
\nPractical voltage-scan voltammetry is not simply linear sweep but cyclic voltammetry (CV), at which applied voltage is reversed at a given voltage in the opposite direction. The theoretical evaluation of the voltammogram should be at first represented in the integral form with the time variation and then express the time as the voltage. One of the features of the diffusion-controlled cyclic voltammograms is the difference between the anodic peak potential and the cathodic one, ΔEp (in Figure 1), of which value is 59 mV at 25°C.
\nVoltammograms calculated from Eq. (5) for v = (a) 180, (b) 80 and (c) 20 mV s−1.
AC voltammetry can be performed when the time variation of voltage is given by E = Edc + V0eiωt, where ω is the frequency of applied AC voltage, i is the imaginary unit, V0 is its voltage amplitude, and Edc is the DC voltage. A conventional value of V0 is 10 mV. When this voltage form is inserted into Eq. (3) together with the Nernst equation, the AC component of the current density is represented by [2].
\nA voltammogram (j vs. Edc) at a given frequency takes a bell shape, which is expressed by sech2{(Edc − Eo)/RT}. The functional form of sech2 is shown in Figure 2. The peak current appears at Edc = Eo.
\nVoltammogram calculated from Eq. (10).
The AC-impedance technique often deals with the real impedance, Z1, = 1/2Y1 and the imaginary one, Z2 = −1/2Y1, where Y1 is the real admittance given by
\nHere Y2 is the imaginary admittance, equal to Y1. Since Z1 = −Z2, the Nyquist plot, i.e., −Z2 vs. Z1, is a line with the slope of unity. The term 1 + i in Eq. (7) has come from (Dω)1/2, originating from (Diω)1/2. Therefore, it can be attributed to diffusion. In other words, diffusion produces the capacitive component as a delay.
\nWhen the redox species with reaction R = O + e− is adsorbed on the electrode and has no influence from the redox species in the solution, the sum of the surface concentrations of R and O is a constant, Γ*. Then the surface concentration of the oxidized species, Γo, is given by the Nernst equation:
\nThe time derivative of the redox charge corresponds to the current density, j = d(FΓo)/dt. Application of the condition of voltage sweep, E = Ein + vt, to Eq. (9) yields.
\nThe voltammogram takes a bell shape (Figure 2), of which peak is at E = Eo, similar to the AC voltammogram. The current at any voltage is proportional to v. Since the negative-going scan of the voltage provides negative current values, the cyclic voltammogram should be symmetric with respect to the I = 0 axis. The peak current is expressed as jp = F2Γ*v/4RT. The width of the wave at jp/2 is 90 mV at 25°C.
\nSince a phase has its own free energy, contact of two phases provides a step-like gap of the free energy, of which gradient brings about infinite magnitude of force. In order to relax the infinity, local free energy varies from one phase to the other as smoothly as possible at the interface. The large variation of the energy is compensated with spontaneously generated space variations of voltage, i.e., the electric field, which works as an electric capacitor. The capacitance at solution-electrode interface causes orientation of dipoles and nonuniform distribution of ionic concentration, of which layer is called an electric double layer (DL).
\nWhen the time variation of the voltage is applied to the DL capacitance, Cd, the definitions of the capacitance (q = CdV) and the current lead
\nwhere Cd generally depends on the time. This dependence is significant for understanding experimentally observed capacitive currents.
\nThe DL capacitance has exhibited the frequency dispersion expressed by Cd = (Cd) 1Hz f −λ, called the constant phase element [3, 4, 5] or power law [6, 7], where λ is close to 0.1. Inserting this expression and V = V0eiωt into Eq. (11) yields
\nThis is a simple sum of the real part of the current and the imaginary one, indicating that the equivalent circuit should be a parallel combination of a capacitive component and a resistive one, both depending on frequency. Since the ratio, −Z2/Z1, for Eq. (12) is 1/λ, the Nyquist plots have slopes less than 10 rather than infinity.
\nIf the capacitive charge is independent of the time, the capacitive current should be I = d(CV)/dt = C(E − Eo)/v. Therefore, it takes a horizontal positive (v > 0) and a negative line (v < 0), as shown in Figure 3 (dashed lines). When the time dependence of C, i.e., Cd = (Cd)0t−λ, is applied to Eq. (11), for the forward and the backward scans, respectively, we have
\nCapacitive voltammograms by CV at v= 0.5 V s−1 for (dashed lines) the ideal capacitance and for Eq. (13) (solid curves) at λ = 0.2.
The variation of CV computed from Eq. (13) (Figure 3, solid curves) is similar to our conventionally observed capacitive waves.
\nVoltammograms can identify an objective species by comparing a peak potential with a table of redox potentials and furthermore determine its concentration from the peak current. Their results are, however, sometimes inconsistent with data by methods other than electrochemical techniques if one falls in some pitfalls of analytical methods of electrochemistry. For example, a peak potential is influenced by a reference electrode and solution resistance relevant to methods. Peak currents are varied complicatedly with mass transport modes as well as associated chemical reactions. Since the theory on voltammetry covers only some restricted experimental conditions, it can rarely interpret the experimental data successfully. This review is devoted to some voltammetric tips which can lead experimenters to reasonable interpretation.
\nIt is rare to observe a reversible voltammogram in which both oxidation and reduction waves appear in a symmetric form with respect to the potential axis at a similar peak potential, as in Figure 1. Frequently observed voltammograms are irreversible, i.e., either a cathodic or an anodic wave appears; a value of a cathodic peak current is quite different from the anodic one in magnitude; a cathodic peak potential is far from the anodic one. These complications are ascribed to chemical reactions and/or phase transformation after the charge-transfer reaction. A typical example is deposition of metal ions on an electrode. The complications can be interpreted by altering scan rates and reverse potentials.
\nA wave at a backward scan is mostly attributed to electrode reactions generated by experimenters rather than to species latently present in the solution. That is, it is artificial. It is caused either by the reaction of the wave at the forward scan or the reaction of the rising-up current just before the reverse potential. A source of the backward wave can be found by changing the reverse potentials.
\nSome voltammograms have more than two peaks at one-directional scan. The appearance of the two can be interpreted as a two-step sequential charge-transfer reaction. However, multiple waves appear also by combinations of chemical reactions and adsorption. The peak current and the charge for this case are quite different from the predicted ones, as will be described in Section 3.2. Change in scan rates may be helpful for interpreting the multiple waves.
\nIt is possible to predict theoretically a controlling step of voltammograms from their shape (a bell type corresponding to an adsorption wave or a draw-out type corresponding to a diffusion wave). However, the shape strongly depends on chemical complications, adsorption, and surface treatment of the electrodes. When redox species in solution is partially adsorbed on an electrode, the electrode process is far from a prediction because of very high concentration in the adsorbed state. A draw-out-shaped wave can be observed even for the adsorbed control. It is important to estimate which state the reacting species takes on the electrode. Potentials representing of voltammetric features do not express a controlling step in reality although the theory does. One should pay attention to the current. The peak current controlled by diffusion with one-electron transfer is given by Ip = 0.27 cAv1/2 μA (c, bulk concentration mM; A, electrode area mm2; v, potential sweep rate mV s−1). The microelectrode behavior sometimes comes in view at v < 10 mV s−1, A < 0.1 mm2, so the measured current is larger than the estimated value. On the other hand, the peak current controlled by adsorption is given by Ip = 1.6 Av nA when one redox molecule is adsorbed at 1 nm2 on the electrode. The voltammogram by adsorption often differs from the ideal bell shape due to adsorbed molecular interaction and DL capacity. Division of the area of the peak by the scan rate yields the amount of adsorbed electricity. Comparison of this with the anticipated amount of adsorption may be helpful for understanding the electrode process.
\nThe peak potential difference ΔEp between the oxidation wave and the reduction wave (Figure 1) has been used for a prediction of the reaction mechanism. For example, ΔEp = 60 mM suggests the diffusion-controlled current accompanied by one-electron exchange, whereas ΔEp = 30 mM infers a simultaneous reaction with two electrons. Then what would happen for 120 mV which is sometimes found? A half-electron reaction might not be accepted. Potential shift over 60 mV occurs by chemical complications. In contrast, the voltammogram by adsorbed species shows theoretically a bell shape with the width, E1/2 = 90 mV, at the half height of the peak (Figure 2). This value is based on the assumption of the absence of interaction among adsorbed species. However, adsorption necessarily yields such high concentrations as strong interaction.
\nIt is necessary to pay attention to the validity of analyzing ΔEp and E1/2. The peak potential is the first derivative of a voltammogram. Since ΔEp is a difference between the two peaks, it is actually the second-order derivative of the curves in the view of accuracy. In other words, the accuracy of ΔEp is lower than that of peak current. Furthermore, peak potentials as well as E1/2 readily vary with scan rates owing to chemical reactions and solution resistance. One should use the peak current for data analysis instead of the potentials.
\nVoltammograms of a number of redox species have been reported to be diffusion controlled from a relationship between Ip and v1/2. The redox species exhibiting diffusion-controlled current is, however, limited to ferrocenyl derivatives under conventional conditions. Voltammograms even for [Fe(CN)6]3−/4− and [Ru(NH3)6]3+ are deviated from the diffusion control for a long-time measurement. Why have many researchers assigned voltammograms to be the diffusion-controlled step? The proportionality of Ip to v1/2 in Eq. (6) has been confused with the linearity, Ip = av1/2 + b (b ≠ 0). The plot for the adsorption control (Ip = kv) also shows approximately a linear relation for Ip vs. v1/2 plot in a narrow domain of v, as shown in Figure 4B. The opposite is true (Figure 4A). Therefore, it is the intercept that determines a controlling step of either the diffusion or adsorption. Some may say that the intercept can be ascribed to a capacitive current. If so, the peak current should be represented by Ip = av1/2 + bv, which exhibits neither linear relation with v1/2 nor v.
\nPlots of Ip of (A) K3Fe(CN)6 and (B) polyaniline-coated electrode against v1/2 and v. Both plots show approximately linear relations.
There is a simple method of determining a controlling step either by diffusion or adsorption. Current responding to diffusion-controlled potential at a disk electrode in diameter less than 0.1 mm would become under the steady state after a few seconds [8]. Adsorption-limited current should become zero soon after the potential application. Many redox species, however, show gradual decrease in the current because reaction products generate an adsorbed layer which blocks further electrode reactions.
\nIt is well known that currents vary not only with applied voltage but also with the time. It is not popular, however, to discuss quantitatively time dependence of CV voltammograms. Enhancing v generally increases the current and causes the peak potential to shift in the direction of the scan. A reason for the former can be interpreted as generation of large current at a shorter time (see Eqs. (6) and (10)), whereas the latter is ascribed to a delay of reaction responses as well as a voltage loss of the reaction by solution resistance. Then the voltage effective to the reaction is lower than the intended voltage, and so the observed current may be smaller than the predicted one. Although Ip is related strongly with Ep, the relationship has rarely been examined quantitatively.
\nA technique of analyzing the potential shift is to plot Ip against Ep, [9] as shown in Figure 5. If the plots on the oxidation side (Ip > 0) and the reduction side (Ip < 0) fall each on a straight line, the slope may represent conductivity. If values of both slopes are equal, the slope possibly stands for the conductivity of the solution or membrane regardless of the electrode reaction. The potential extrapolated to the zero current on each straight line should be close to the formal potential. Since this plot is simple technically, the analytical result is more reliable than at least discussion of time dependence of Ep.
\nPlots of Ip vs. Ep by CV of the first (circles) and the second (triangles) peak of tetracyanoquinodimethane (TCNQ), and ferrocene (squares) in 0.2 M (CH3)4NPF6 included acetonitrile solution when scan rates were varied, where triangles were displayed by 0.4 V shift.
Most researchers have quoted the Randles-Sevcik equation, jp = 0.446 (nF)3/2c*(Dv/RT)1/2, for the diffusion-controlled peak current without hesitation, where n is the electron transfer number of the reaction. According to Faraday’s law, the electrolytic quantity is proportional to nc*. Why is the peak current proportional to n3/2 instead of n? Let us consider voltammetry of metal nanoparticles (about 25 nm in diameter) composed of 106 metal atoms dispersed in solution. Faraday’s law predicts that the current is 106 times as high as the current by the one metal atom. However, Randles-Sevcik equation predicts the current further (106)1/2 = 1000 times as large, just by the effect of the potential scan. The order 3/2 is specific to CV. The order of n for AC current and pulse voltammetry is 2 [10]. On the other hand, the diffusion-controlled steady-state currents at a microelectrode and a rotating disk electrode are proportional to n. Comparing the differences in the order by methods, we can predict that the time variation of the voltage increases the power of n.
\nLet a potential width from a current-rising potential to Ep be denoted by ΔE. When an n-electron transfer reaction occurs through the Nernst equation at which F in Eq. (1) is replaced by nF, the concentration-potential curve takes the slope n times larger than that at n = 1 (see co/cr ≅ nF(E − Eo)/RT near E = Eo in Eq. (1)). Then we have (ΔE)n = (ΔE)n = 1/n. The period of elapsing for (ΔE)n becomes shorter by 1/n, as if v might be larger by n times. Then v in Eq. (6) should be replaced by (nv)1/2. Combining this result with the flux j/nF, the current becomes n3/2 times larger than that at n = 1. Therefore, the factor n3/2 results from the Nernst equation. This can be understood quantitatively by replacing F in Eq. (3) by nF. There are quite a few reactions for n ≥ 2 both for Nernst equation and in the bulk as stable species. The term n3/2 is valid only for a concomitant charge-transfer reaction, i.e., simultaneous occurrence n-electron transfer rather than a step-by-step transfer. Apparent two-electron transfer reactions in the bulk, for example, Cu, Fe, Zn, and Pb, cause other reactions immediately after the one-electron transfer.
\nAn electrochemical response is observed as a sum of the half reactions at the two electrodes. In order to extract the reaction at the working electrode, a conventional technique is to increase the area of the counter electrode so that the reaction at the counter electrode can be ignored. If the counter electrode area is increased by 20 times the area of the working electrode, the observed current represents the reaction of the working electrode with an error of 5%. Let us consider the experiment in which nanoparticles of metal are coated on a working electrode for obtaining capacitive currents or catalyst currents. Then, the actual area of the working electrode can be regarded as the area of the metal particles measured by the molecular level. Then, the area will be several thousand times the geometric area so that the observed current may represent the reaction at the counter electrode. This kind of research has frequently been found in work on supercapacitors. On the other hand, if the electrode reaction is diffusion controlled, the current is determined by the projected area of the diffusion layer. Then the current is not affected by the huge surface area of nanoparticles.
\nIt is important to examine whether or not a reaction is controlled by at a counter electrode. A simple method is to coat nanoparticles also on the counter electrode. Then the current in the solution may become so high that the potential of the working electrode cannot be controlled. It is better to use a two-electrode system. Products at the counter electrode are possible sources of contaminants through redox cycling.
\nThe Ag-AgCl electrode is most frequently used as a reference electrode in aqueous solution because of the stable voltage at interfaces of Ag-AgCl and AgCl-KCl through fast charge-transfer steps, regardless of the magnitude of current density. The “fast step” means the absence of delay of the reaction or being in a quasi-equilibrium. The stability without delay is supported with high concentration of KCl.
\nWhen an Ag-AgCl electrode is inserted to a voltammetric solution, KCl necessarily diffuses into the solution, associated with oxygen from the reference electrode. Thus, the reference electrode is a source of contamination by salt, dichlorosilver and oxygen. It is interesting to examine how much amount a solution is contaminated by a reference electrode [9]. Time variation of ionic conductivity in the pure water was monitored immediately after a commercially available Ag-AgCl electrode was inserted into the solution. Figure 6 shows rapid increase in the conductivity as if a solid of KCl was added to the solution. Oxygen included in the concentrated KCl may contaminate a test solution. Even the Ag-AgxO electrode, which was formed by oxidizing silver wire, increased also the conductivity, probably because the surface is in the form of silver hydroxide. As a result, no reference electrode can be used for studying salt-free electrode reactions. If neutral redox species such as ferrocene is included in a solution, the potential reference can be taken from redox potential of ferrocene.
\nTime-variation of conductivity of water into which (circles) Ag|AgCl, (triangles) Ag|AgxO, and (squares) AgCl-coated Ag wire were inserted. Conductivity measurement was under N2 environment.
When a constant voltage is applied to the ideal capacitance C, the responding current decays in the form of exp(−t/RC), where R is a resistance in series connected with C. It has been believed that a double-layer capacitance in electrochemical system behaves as an ideal capacitor, where R is regarded as solution resistance. However, any exponential variation cannot reproduce transient currents obtained at the platinum wire electrode in KCl aqueous solution, as shown in Figure 7. The current decays more slowly than by exp(−t/RC), because it is approximately proportional to 1/t. The property of non-ideal capacitance is the result of the constant phase element of the DL capacitance, as described in Section 2.3. The dependence of 1/t can be obtained approximately by the time derivative of q = V0C0t−λ for the voltage step V0.
\nChronoamperometric curves when 0.2 V vs. Ag|AgCl was applied to a Pt wire in 0.5 M KCl aqueous solution. Solid curves are fitted ones by exp(-t/RC) for three values of RC.
The slow decay is related with a loss of the performance of pulse voltammetry, in which diffusion-controlled currents can readily be excluded from capacitive currents. The advantage of pulse voltammetry is based on the assumption of the exponential decay of the capacitive current. Since the diffusion current with 1/t1/2 dependence is close to the 1/t dependence, it cannot readily be separated from the capacitive current in reality. A key of using pulse voltammetry is to take a pulse time to be so long as a textbook recommends.
\nHigh-performance potentiostats are equipped with a circuit for compensation of resistance by a positive feedback. Unfortunately, the circuit is merely useful because voltammograms depend on intensity of compensation resistances of the DL capacitance. It should work well if the DL capacitance is ideal.
\nAC techniques have an advantage of examining time dependence at a given potential, whereas CV has a feature of finding current-voltage curves at a given time. The former shows the dynamic range from 1 Hz to 10 kHz, while the latter does conventionally from 0.01 to 1 Hz. This wide dynamic range of the AC technique is powerful for examining dynamics of electrode reactions. Analytical results by the former are often inconsistent with those by the latter, because of the difference in the time domain. The other scientific advantage of the AC technique is to get two types of independent data set, frequency variations of real components and imaginary ones by the use of a lock-in amplification. The independence allows us to operate mathematically the two data, leading to the data analysis at a level one step higher than CV. An industrial advantage is the rapid measurement, which can be applied to quality control for a number of samples. The analysis of AC impedance necessarily needs equivalent circuits of which components do not have any direction relation with electrochemical variables.
\nData of the electrochemical AC impedance are represented by Nyquist (Cole-Cole) plots, that is, plots of the imaginary component (Z2) of the impedance against the real one (Z1), as shown in Figure 8. The simplest equivalent circuit for electrochemical systems is the DL capacitance Cd in series with the solution resistance RS. The Nyquist plot for this series circuit is theoretically parallel to the vertical axis (Figure 8A-a), but experiments show a slope of 5 or more (Figure 8A-b). This behavior, called constant phase element (CPE) and the power law, has been verified for combinations of various materials and solvents [6, 7, 11, 12]. The equivalent circuit for Eq. (12) is a parallel combination of capacitance and resistance (Figure 8B). Even without an electrode reaction, current always includes a real component.
\n(A) Nyquist plots for a RC-series circuit with ideal capacitor (a) and DL capacitor (b). (B) Equivalent circuit with the power-law of Cd. (C) Randles circuit.
The equivalent circuit with the Randles type is a parallel combination of the ideal DL capacitor Cd with the ideal resistance Rct representing the Butler-Volmer-type charge-transfer resistance. Practically, the Warburg impedance (the inverse of Eq. (8)) due to diffusion of redox species is incorporated in a series into Rct (Figure 8C). Rct cannot be separated from the DL resistance because of the frequency dispersion. Since even the existence of Rct is in question (Section 3.12), it is difficult to determine and interpret Rct. The usage of a software that can analyze any Nyquist plots will provide values of R and C. Even if analyzed values are in high accuracy, researches should give them electrochemical significance.
\nResidual current varies with treatments of electrodes such as polishing of electrode surfaces and voltage applications to an extremely high domain. It can often be suppressed to yield reproducible data when the electrode is replaced by simple platinum wire or carbon rod having the same geometric area. Simple wire electrodes are quite useful especially for measurements of DL capacitance and adsorption. One of the reasons for setting off large residual current is that the insulator of confining the active area is not in close contact with the electrode, so that the solution penetrated into the gap will give rise to capacitive current and floating electrode reactions. Since the coefficient of thermal expansion of the electrode is different from that of the insulator, the residual current tends to get large with the elapse from the fabrication of the electrode. This prediction is based on experience, and there are few quantitative studies on residual currents.
\nUnexpected gap has been a technical problem at dropping mercury electrodes. If solution penetrates the inner wall of the glass capillary containing mercury, observed currents become irreproducible. Water repellency of the capillary tip has been known to improve the irreproducibility in order to reduce the penetration. A similar technique has been used for voltammetry at oil-water interfaces and ionic liquid-water interfaces at present.
\nVoltammograms are said to vary with electrode reaction rates, and the rate constants have been determined from time dependence of voltammograms. The fast reaction of which rate is not rate determining has historically been called “reversible.” In contrast, such a slow reaction that a peak potential varies linearly with log v is called “irreversible.” A reaction between them is called “quasi-reversible.” The distinction among the three has been well known since the theoretical report on the quasi-reversible reaction by Matsuda [1]. This theory is devoted to solving the diffusion equations with boundary conditions of the Butler-Volmer (BV) equation under the potential sweep. As the standard rate constant ks in the BV equation becomes small, the peak shifts in the direction of the potential sweep from the diffusion-controlled peak. Steady-state current-potential curves in a microelectrode [13] and a rotating disk electrode also shift the potential in a similar way. According to the calculated CV voltammograms in Figure 9, we can present some characteristics: (i) if the oxidation wave shifts to the positive potential, the negative potential shift should also be found in the reduction wave. (ii) Both the amounts of the shift should have a linear relationship to log v. (iii) The shift should be found in iterative measurements. (iv) The peak current should be proportional to v1/2.
\nCV voltammograms (solid curves) at a normally sized electrode and steady-state voltammograms (dashed curves) at a microelectrodes in 12 μm in diameter, calculated theoretically for v = 0.5 V s−1, D = 0.73 × 10−5 cm2 s−1, ks = (a) 0.1, (b) 0.01, (c) 0.001, (d) 0.0001 cm s−1. The potential shift of CV is equivalent to the wave-shift at a microelectrode through the relation, v = 0.4RTD/αFa2 (a: radius).
The authors attempted to find a redox species with the above four behaviors. Some redox species can satisfy one of the four requirements, but do not meet the others. Most reaction rate constants have been determined from the potential shift in a narrow time domain. They are probably caused by follow-up chemical reactions, adsorption, or DL capacitance. For example, CV peak potentials of TCNQ and benzoquinone were shifted at high scan rates, whereas their steady-state voltammograms were independent of diameters of microdisk electrodes even on the nanometer scale [14]. The shift at high scan rates should be due to the frequency dispersion of the DL capacitance, especially the parallel resistance in the DL (Figure 8B). Values of the heterogeneous rate constants and transfer coefficients reported so far have depended not only on the electrochemical techniques but also research groups. Furthermore, they have not been applied or extended to next developing work. These facts inspire us to examine the assumptions and validity of the BV formula.
\nLet us revisit the assumptions of the BV equation when an overvoltage, i.e., the difference of the applied potential from the standard electrode potential, causes the electrode reaction. The rate of the oxidation in the BV equation is assumed to have the activation energy of α times the overvoltage, while that of the reduction does that of (1 − α) times. This assumption seems reasonable for the balance of both the oxidation and the reduction. However, the following two points should be considered. (i) Once a charge or an electron is transferred within the redox species, the molecular structure changes more slowly than the charge transfer itself occurs. The structure change causes solvation as well as motion of external ions to keep electric neutrality. These processes should be slower than the structure change. If the overvoltage can control the reaction rate, it should act on to the slowest step, which is not the genuine charge-transfer process. (ii) Since a reaction rate belongs to the probability theory, the reaction rate (dc/dt) at t is determined with the state at t rather than a state in the future. In other words, the rate of the reduction should have no relation with the oxidation state which belongs to the future state. The BV theory assumes that the α times activation energy for the oxidation is related closely with 1-α times one for the reduction. This assumption is equivalent to predicting a state at t + Δt from state at t + 2Δt, like riding on a time machine. This question should be solved from a viewpoint of statistical physics.
\nDevelopment of scanning microscopes such as STM and AFM has allowed us to obtain the molecularly and atomically regulated surface images, which have been used for interpreting electrochemical data. Then the electrochemical data are expected to be discussed on a molecular scale. However, there is an essential problem of applying photographs of regularly arranged atoms on an electrode to electrochemical data, because the former and the latter include, respectively, microscopically local information and macroscopically averaged one. A STM image showing molecular patterns is information of only a part of electrode, at next parts of which no atomic images are often observed but noisy images are found. Electrochemical data should be composed of information both at a part of the electrode showing the molecular patters and at other parts showing noisy, vague images. Noisy photographs are always discarded for interpreting electrochemical data although the surfaces with noisy images also contribute electrochemical data.
\nAn ideal experiment would be made by taking STM images over all the electrodes that provide electrochemical data and by obtaining an averaged image. However, it is not only impossible to take huge amounts of images, but the averaged image might be also noisy. It may be helpful to describe only a possibility of reflecting the STM-imaged atomic structure on the electrochemical data.
\nVoltammograms by adsorbed redox species, called surface waves, are frequently different from a bell shape (Figure 2). Really observed features are the following: (i) the voltammogram does not suddenly decay after the peak, exhibiting a tail-like diffusional wave; (ii) the peak current and the amount of the electricity are proportional to the power less than the unity of v; (iii) the oxidation peak potential is different from the reduction one; (iv) the background current cannot be determined unequivocally; and (v) voltammograms depend on the starting potential. Why are experimental surface waves different from a symmetric, bell shape in Figure 2?
\nA loss of the symmetry with respect to the vertical line passing through a peak can be ascribed to the difference in interactions at the oxidized potential domain and at the reduced one. Since redox species takes extremely high concentration in the adsorbed layer, interaction is highly influenced on voltammetric form. When the left-right asymmetry is ascribed to thermodynamic interaction, it has been interpreted not only with Frumkin’s interaction [15] but also Bragg-Williams-like model for the nearest neighboring interactive redox species [16]. On the other hand, most surface waves are asymmetric with respect to the voltage axis even at extremely slow scan rates. This asymmetry cannot be explained in terms of thermodynamics of intermolecular interaction, but should resort to kinetics or a delay of electrode reactions. There seems to be no delay in the electrode reaction of the monomolecular adsorption layer, different from diffusion species. The delay resembles the phenomenon of constant phase element (CPE) or frequency power law of DL capacitance, in that the redox interaction may occur two-dimensionally so that the most stable state can be attained. This behavior belongs to a cooperative phenomenon [17]. A technique of overcoming these complications is to discuss the amount of charge by evaluating the area of the voltammogram. It also includes ambiguity of eliminating background current and assuming the independence of the redox charge from the DL charge.
\nThe simplest theories for voltammetry are limited to the rate-determining steps of diffusion of redox species and reactions of adsorbed species without interaction. Variation of scan rates as well as a reverse potential is helpful for predicting redox species and reaction mechanisms. Furthermore, the following viewpoints are useful for interpreting mechanisms:
comparison of values of experimental peak currents with theoretical ones, instead of discussing ΔEp and E1/2;
examining the proportionality of Ip vs. v or vs. v1/2, i.e., zero or non-zero values of the intercept of the linearity;
a reference electrode and a counter electrode being a source of contamination in solution;
attention to very slow relaxation of DL capacitive currents;
inclusion of ambiguity in the equivalent circuit with the Randles type.
License
\n\nBook Chapters published in edited volumes are distributed under the Creative Commons Attribution 3.0 Unported License (CC BY 3.0). IntechOpen maintains a very flexible Copyright Policy that ensures that there is no copyright transfer to the publisher. Therefore, Authors retain exclusive copyright to their work. All Monographs are distributed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0).
\n\n',metaTitle:"Open Access Statement",metaDescription:"Book chapters published in edited volumes are distributed under the Creative Commons Attribution 3.0 Unported License (CC BY 3.0)",metaKeywords:null,canonicalURL:"/page/open-access-statement/",contentRaw:'[{"type":"htmlEditorComponent","content":"Formats
\\n\\nBased on your preferences and the stage of your scientific projects, you have multiple options for publishing your scientific research with IntechOpen:
\\n\\nPeer Review Policies
\\n\\nAll scientific Works are subject to Peer Review prior to publishing.
\\n\\n\\n\\nCosts
\\n\\nThe Open Access publishing model followed by IntechOpen eliminates subscription charges and pay-per-view fees, thus enabling readers to access research at no cost to themselves. In order to sustain these operations, and keep our publications freely accessible, we levy an Open Access Publishing Fee on all manuscripts accepted for publication to help cover the costs of editorial work and the production of books.
\\n\\n\\n\\nDigital Archiving Policy
\\n\\nIntechOpen is dedicated to ensuring the long-term preservation and availability of the scholarly research it publishes.
\\n"}]'},components:[{type:"htmlEditorComponent",content:'Formats
\n\nBased on your preferences and the stage of your scientific projects, you have multiple options for publishing your scientific research with IntechOpen:
\n\nPeer Review Policies
\n\nAll scientific Works are subject to Peer Review prior to publishing.
\n\n\n\nCosts
\n\nThe Open Access publishing model followed by IntechOpen eliminates subscription charges and pay-per-view fees, thus enabling readers to access research at no cost to themselves. In order to sustain these operations, and keep our publications freely accessible, we levy an Open Access Publishing Fee on all manuscripts accepted for publication to help cover the costs of editorial work and the production of books.
\n\n\n\nDigital Archiving Policy
\n\nIntechOpen is dedicated to ensuring the long-term preservation and availability of the scholarly research it publishes.
\n'}]},successStories:{items:[]},authorsAndEditors:{filterParams:{sort:"featured,name"},profiles:[{id:"6700",title:"Dr.",name:"Abbass A.",middleName:null,surname:"Hashim",slug:"abbass-a.-hashim",fullName:"Abbass A. Hashim",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/6700/images/1864_n.jpg",biography:"Currently I am carrying out research in several areas of interest, mainly covering work on chemical and bio-sensors, semiconductor thin film device fabrication and characterisation.\nAt the moment I have very strong interest in radiation environmental pollution and bacteriology treatment. The teams of researchers are working very hard to bring novel results in this field. I am also a member of the team in charge for the supervision of Ph.D. students in the fields of development of silicon based planar waveguide sensor devices, study of inelastic electron tunnelling in planar tunnelling nanostructures for sensing applications and development of organotellurium(IV) compounds for semiconductor applications. I am a specialist in data analysis techniques and nanosurface structure. I have served as the editor for many books, been a member of the editorial board in science journals, have published many papers and hold many patents.",institutionString:null,institution:{name:"Sheffield Hallam University",country:{name:"United Kingdom"}}},{id:"54525",title:"Prof.",name:"Abdul Latif",middleName:null,surname:"Ahmad",slug:"abdul-latif-ahmad",fullName:"Abdul Latif Ahmad",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"20567",title:"Prof.",name:"Ado",middleName:null,surname:"Jorio",slug:"ado-jorio",fullName:"Ado Jorio",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universidade Federal de Minas Gerais",country:{name:"Brazil"}}},{id:"47940",title:"Dr.",name:"Alberto",middleName:null,surname:"Mantovani",slug:"alberto-mantovani",fullName:"Alberto Mantovani",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"12392",title:"Mr.",name:"Alex",middleName:null,surname:"Lazinica",slug:"alex-lazinica",fullName:"Alex Lazinica",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/12392/images/7282_n.png",biography:"Alex Lazinica is the founder and CEO of IntechOpen. After obtaining a Master's degree in Mechanical Engineering, he continued his PhD studies in Robotics at the Vienna University of Technology. Here he worked as a robotic researcher with the university's Intelligent Manufacturing Systems Group as well as a guest researcher at various European universities, including the Swiss Federal Institute of Technology Lausanne (EPFL). During this time he published more than 20 scientific papers, gave presentations, served as a reviewer for major robotic journals and conferences and most importantly he co-founded and built the International Journal of Advanced Robotic Systems- world's first Open Access journal in the field of robotics. Starting this journal was a pivotal point in his career, since it was a pathway to founding IntechOpen - Open Access publisher focused on addressing academic researchers needs. Alex is a personification of IntechOpen key values being trusted, open and entrepreneurial. Today his focus is on defining the growth and development strategy for the company.",institutionString:null,institution:{name:"TU Wien",country:{name:"Austria"}}},{id:"19816",title:"Prof.",name:"Alexander",middleName:null,surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/19816/images/1607_n.jpg",biography:"Alexander I. Kokorin: born: 1947, Moscow; DSc., PhD; Principal Research Fellow (Research Professor) of Department of Kinetics and Catalysis, N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow.\r\nArea of research interests: physical chemistry of complex-organized molecular and nanosized systems, including polymer-metal complexes; the surface of doped oxide semiconductors. He is an expert in structural, absorptive, catalytic and photocatalytic properties, in structural organization and dynamic features of ionic liquids, in magnetic interactions between paramagnetic centers. The author or co-author of 3 books, over 200 articles and reviews in scientific journals and books. He is an actual member of the International EPR/ESR Society, European Society on Quantum Solar Energy Conversion, Moscow House of Scientists, of the Board of Moscow Physical Society.",institutionString:null,institution:{name:"Semenov Institute of Chemical Physics",country:{name:"Russia"}}},{id:"62389",title:"PhD.",name:"Ali Demir",middleName:null,surname:"Sezer",slug:"ali-demir-sezer",fullName:"Ali Demir Sezer",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/62389/images/3413_n.jpg",biography:"Dr. Ali Demir Sezer has a Ph.D. from Pharmaceutical Biotechnology at the Faculty of Pharmacy, University of Marmara (Turkey). He is the member of many Pharmaceutical Associations and acts as a reviewer of scientific journals and European projects under different research areas such as: drug delivery systems, nanotechnology and pharmaceutical biotechnology. Dr. Sezer is the author of many scientific publications in peer-reviewed journals and poster communications. Focus of his research activity is drug delivery, physico-chemical characterization and biological evaluation of biopolymers micro and nanoparticles as modified drug delivery system, and colloidal drug carriers (liposomes, nanoparticles etc.).",institutionString:null,institution:{name:"Marmara University",country:{name:"Turkey"}}},{id:"61051",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"100762",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"St David's Medical Center",country:{name:"United States of America"}}},{id:"107416",title:"Dr.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Texas Cardiac Arrhythmia",country:{name:"United States of America"}}},{id:"64434",title:"Dr.",name:"Angkoon",middleName:null,surname:"Phinyomark",slug:"angkoon-phinyomark",fullName:"Angkoon Phinyomark",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/64434/images/2619_n.jpg",biography:"My name is Angkoon Phinyomark. I received a B.Eng. degree in Computer Engineering with First Class Honors in 2008 from Prince of Songkla University, Songkhla, Thailand, where I received a Ph.D. degree in Electrical Engineering. My research interests are primarily in the area of biomedical signal processing and classification notably EMG (electromyography signal), EOG (electrooculography signal), and EEG (electroencephalography signal), image analysis notably breast cancer analysis and optical coherence tomography, and rehabilitation engineering. I became a student member of IEEE in 2008. During October 2011-March 2012, I had worked at School of Computer Science and Electronic Engineering, University of Essex, Colchester, Essex, United Kingdom. In addition, during a B.Eng. I had been a visiting research student at Faculty of Computer Science, University of Murcia, Murcia, Spain for three months.\n\nI have published over 40 papers during 5 years in refereed journals, books, and conference proceedings in the areas of electro-physiological signals processing and classification, notably EMG and EOG signals, fractal analysis, wavelet analysis, texture analysis, feature extraction and machine learning algorithms, and assistive and rehabilitative devices. I have several computer programming language certificates, i.e. Sun Certified Programmer for the Java 2 Platform 1.4 (SCJP), Microsoft Certified Professional Developer, Web Developer (MCPD), Microsoft Certified Technology Specialist, .NET Framework 2.0 Web (MCTS). I am a Reviewer for several refereed journals and international conferences, such as IEEE Transactions on Biomedical Engineering, IEEE Transactions on Industrial Electronics, Optic Letters, Measurement Science Review, and also a member of the International Advisory Committee for 2012 IEEE Business Engineering and Industrial Applications and 2012 IEEE Symposium on Business, Engineering and Industrial Applications.",institutionString:null,institution:{name:"Joseph Fourier University",country:{name:"France"}}},{id:"55578",title:"Dr.",name:"Antonio",middleName:null,surname:"Jurado-Navas",slug:"antonio-jurado-navas",fullName:"Antonio Jurado-Navas",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/55578/images/4574_n.png",biography:"Antonio Jurado-Navas received the M.S. degree (2002) and the Ph.D. degree (2009) in Telecommunication Engineering, both from the University of Málaga (Spain). He first worked as a consultant at Vodafone-Spain. From 2004 to 2011, he was a Research Assistant with the Communications Engineering Department at the University of Málaga. In 2011, he became an Assistant Professor in the same department. From 2012 to 2015, he was with Ericsson Spain, where he was working on geo-location\ntools for third generation mobile networks. Since 2015, he is a Marie-Curie fellow at the Denmark Technical University. His current research interests include the areas of mobile communication systems and channel modeling in addition to atmospheric optical communications, adaptive optics and statistics",institutionString:null,institution:{name:"University of Malaga",country:{name:"Spain"}}}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:5766},{group:"region",caption:"Middle and South America",value:2,count:5228},{group:"region",caption:"Africa",value:3,count:1717},{group:"region",caption:"Asia",value:4,count:10370},{group:"region",caption:"Australia and Oceania",value:5,count:897},{group:"region",caption:"Europe",value:6,count:15791}],offset:12,limit:12,total:118192},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{hasNoEditors:"0",sort:"ebgfFaeGuveeFgfcChcyvfu"},books:[],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:6},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:6},{group:"topic",caption:"Business, Management and Economics",value:7,count:4},{group:"topic",caption:"Chemistry",value:8,count:1},{group:"topic",caption:"Computer and Information Science",value:9,count:5},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:3},{group:"topic",caption:"Engineering",value:11,count:4},{group:"topic",caption:"Environmental Sciences",value:12,count:4},{group:"topic",caption:"Immunology and Microbiology",value:13,count:2},{group:"topic",caption:"Mathematics",value:15,count:2},{group:"topic",caption:"Medicine",value:16,count:26},{group:"topic",caption:"Neuroscience",value:18,count:1},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:3},{group:"topic",caption:"Physics",value:20,count:2},{group:"topic",caption:"Psychology",value:21,count:3},{group:"topic",caption:"Robotics",value:22,count:4},{group:"topic",caption:"Social Sciences",value:23,count:3},{group:"topic",caption:"Technology",value:24,count:1}],offset:0,limit:12,total:null},popularBooks:{featuredBooks:[{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9671",title:"Macrophages",subtitle:null,isOpenForSubmission:!1,hash:"03b00fdc5f24b71d1ecdfd75076bfde6",slug:"macrophages",bookSignature:"Hridayesh Prakash",coverURL:"https://cdn.intechopen.com/books/images_new/9671.jpg",editors:[{id:"287184",title:"Dr.",name:"Hridayesh",middleName:null,surname:"Prakash",slug:"hridayesh-prakash",fullName:"Hridayesh Prakash"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9313",title:"Clay Science and Technology",subtitle:null,isOpenForSubmission:!1,hash:"6fa7e70396ff10620e032bb6cfa6fb72",slug:"clay-science-and-technology",bookSignature:"Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/9313.jpg",editors:[{id:"7153",title:"Prof.",name:"Gustavo",middleName:null,surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9027",title:"Human Blood Group Systems and Haemoglobinopathies",subtitle:null,isOpenForSubmission:!1,hash:"d00d8e40b11cfb2547d1122866531c7e",slug:"human-blood-group-systems-and-haemoglobinopathies",bookSignature:"Osaro Erhabor and Anjana Munshi",coverURL:"https://cdn.intechopen.com/books/images_new/9027.jpg",editors:[{id:"35140",title:null,name:"Osaro",middleName:null,surname:"Erhabor",slug:"osaro-erhabor",fullName:"Osaro Erhabor"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7841",title:"New Insights Into Metabolic Syndrome",subtitle:null,isOpenForSubmission:!1,hash:"ef5accfac9772b9e2c9eff884f085510",slug:"new-insights-into-metabolic-syndrome",bookSignature:"Akikazu Takada",coverURL:"https://cdn.intechopen.com/books/images_new/7841.jpg",editors:[{id:"248459",title:"Dr.",name:"Akikazu",middleName:null,surname:"Takada",slug:"akikazu-takada",fullName:"Akikazu Takada"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8558",title:"Aerodynamics",subtitle:null,isOpenForSubmission:!1,hash:"db7263fc198dfb539073ba0260a7f1aa",slug:"aerodynamics",bookSignature:"Mofid Gorji-Bandpy and Aly-Mousaad Aly",coverURL:"https://cdn.intechopen.com/books/images_new/8558.jpg",editors:[{id:"35542",title:"Prof.",name:"Mofid",middleName:null,surname:"Gorji-Bandpy",slug:"mofid-gorji-bandpy",fullName:"Mofid Gorji-Bandpy"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7847",title:"Medical Toxicology",subtitle:null,isOpenForSubmission:!1,hash:"db9b65bea093de17a0855a1b27046247",slug:"medical-toxicology",bookSignature:"Pınar Erkekoglu and Tomohisa Ogawa",coverURL:"https://cdn.intechopen.com/books/images_new/7847.jpg",editors:[{id:"109978",title:"Prof.",name:"Pınar",middleName:null,surname:"Erkekoglu",slug:"pinar-erkekoglu",fullName:"Pınar Erkekoglu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10432",title:"Casting Processes and Modelling of Metallic Materials",subtitle:null,isOpenForSubmission:!1,hash:"2c5c9df938666bf5d1797727db203a6d",slug:"casting-processes-and-modelling-of-metallic-materials",bookSignature:"Zakaria Abdallah and Nada Aldoumani",coverURL:"https://cdn.intechopen.com/books/images_new/10432.jpg",editors:[{id:"201670",title:"Dr.",name:"Zak",middleName:null,surname:"Abdallah",slug:"zak-abdallah",fullName:"Zak Abdallah"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:5240},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9671",title:"Macrophages",subtitle:null,isOpenForSubmission:!1,hash:"03b00fdc5f24b71d1ecdfd75076bfde6",slug:"macrophages",bookSignature:"Hridayesh Prakash",coverURL:"https://cdn.intechopen.com/books/images_new/9671.jpg",editors:[{id:"287184",title:"Dr.",name:"Hridayesh",middleName:null,surname:"Prakash",slug:"hridayesh-prakash",fullName:"Hridayesh Prakash"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9313",title:"Clay Science and Technology",subtitle:null,isOpenForSubmission:!1,hash:"6fa7e70396ff10620e032bb6cfa6fb72",slug:"clay-science-and-technology",bookSignature:"Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/9313.jpg",editors:[{id:"7153",title:"Prof.",name:"Gustavo",middleName:null,surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9027",title:"Human Blood Group Systems and Haemoglobinopathies",subtitle:null,isOpenForSubmission:!1,hash:"d00d8e40b11cfb2547d1122866531c7e",slug:"human-blood-group-systems-and-haemoglobinopathies",bookSignature:"Osaro Erhabor and Anjana Munshi",coverURL:"https://cdn.intechopen.com/books/images_new/9027.jpg",editors:[{id:"35140",title:null,name:"Osaro",middleName:null,surname:"Erhabor",slug:"osaro-erhabor",fullName:"Osaro Erhabor"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10432",title:"Casting Processes and Modelling of Metallic Materials",subtitle:null,isOpenForSubmission:!1,hash:"2c5c9df938666bf5d1797727db203a6d",slug:"casting-processes-and-modelling-of-metallic-materials",bookSignature:"Zakaria Abdallah and Nada Aldoumani",coverURL:"https://cdn.intechopen.com/books/images_new/10432.jpg",editors:[{id:"201670",title:"Dr.",name:"Zak",middleName:null,surname:"Abdallah",slug:"zak-abdallah",fullName:"Zak Abdallah"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7841",title:"New Insights Into Metabolic Syndrome",subtitle:null,isOpenForSubmission:!1,hash:"ef5accfac9772b9e2c9eff884f085510",slug:"new-insights-into-metabolic-syndrome",bookSignature:"Akikazu Takada",coverURL:"https://cdn.intechopen.com/books/images_new/7841.jpg",editors:[{id:"248459",title:"Dr.",name:"Akikazu",middleName:null,surname:"Takada",slug:"akikazu-takada",fullName:"Akikazu Takada"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editedByType:"Edited by",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editedByType:"Edited by",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editedByType:"Edited by",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editedByType:"Edited by",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9669",title:"Recent Advances in Rice Research",subtitle:null,isOpenForSubmission:!1,hash:"12b06cc73e89af1e104399321cc16a75",slug:"recent-advances-in-rice-research",bookSignature:"Mahmood-ur- Rahman Ansari",coverURL:"https://cdn.intechopen.com/books/images_new/9669.jpg",editedByType:"Edited by",editors:[{id:"185476",title:"Dr.",name:"Mahmood-Ur-",middleName:null,surname:"Rahman Ansari",slug:"mahmood-ur-rahman-ansari",fullName:"Mahmood-Ur- Rahman Ansari"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editedByType:"Edited by",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editedByType:"Edited by",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editedByType:"Edited by",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9313",title:"Clay Science and Technology",subtitle:null,isOpenForSubmission:!1,hash:"6fa7e70396ff10620e032bb6cfa6fb72",slug:"clay-science-and-technology",bookSignature:"Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/9313.jpg",editedByType:"Edited by",editors:[{id:"7153",title:"Prof.",name:"Gustavo",middleName:null,surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editedByType:"Edited by",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"119",title:"Industrial Engineering and Management",slug:"industrial-engineering-and-management",parent:{title:"Engineering",slug:"engineering"},numberOfBooks:48,numberOfAuthorsAndEditors:1096,numberOfWosCitations:1145,numberOfCrossrefCitations:783,numberOfDimensionsCitations:1680,videoUrl:null,fallbackUrl:null,description:null},booksByTopicFilter:{topicSlug:"industrial-engineering-and-management",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editedByType:"Edited by",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9423",title:"AI and Learning Systems",subtitle:"Industrial Applications and Future Directions",isOpenForSubmission:!1,hash:"10ac8fb0bdbf61044395963028653d21",slug:"ai-and-learning-systems-industrial-applications-and-future-directions",bookSignature:"Konstantinos Kyprianidis and Erik Dahlquist",coverURL:"https://cdn.intechopen.com/books/images_new/9423.jpg",editedByType:"Edited by",editors:[{id:"35868",title:"Prof.",name:"Konstantinos",middleName:"G.",surname:"Kyprianidis",slug:"konstantinos-kyprianidis",fullName:"Konstantinos Kyprianidis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9279",title:"Concepts, Applications and Emerging Opportunities in Industrial Engineering",subtitle:null,isOpenForSubmission:!1,hash:"9bfa87f9b627a5468b7c1e30b0eea07a",slug:"concepts-applications-and-emerging-opportunities-in-industrial-engineering",bookSignature:"Gary Moynihan",coverURL:"https://cdn.intechopen.com/books/images_new/9279.jpg",editedByType:"Edited by",editors:[{id:"16974",title:"Dr.",name:"Gary",middleName:null,surname:"Moynihan",slug:"gary-moynihan",fullName:"Gary Moynihan"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9174",title:"Product Design",subtitle:null,isOpenForSubmission:!1,hash:"3510bacbbf4d365e97510bf962652de1",slug:"product-design",bookSignature:"Cătălin Alexandru, Codruta Jaliu and Mihai Comşit",coverURL:"https://cdn.intechopen.com/books/images_new/9174.jpg",editedByType:"Edited by",editors:[{id:"2767",title:"Prof.",name:"Catalin",middleName:null,surname:"Alexandru",slug:"catalin-alexandru",fullName:"Catalin Alexandru"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8623",title:"Maintenance Management",subtitle:null,isOpenForSubmission:!1,hash:"91cc93ad76fdd6709b8c50c6ba7e4e0c",slug:"maintenance-management",bookSignature:"Fausto Pedro García Márquez and Mayorkinos Papaelias",coverURL:"https://cdn.intechopen.com/books/images_new/8623.jpg",editedByType:"Edited by",editors:[{id:"22844",title:"Prof.",name:"Fausto Pedro",middleName:null,surname:"García Márquez",slug:"fausto-pedro-garcia-marquez",fullName:"Fausto Pedro García Márquez"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7441",title:"Micromachining",subtitle:null,isOpenForSubmission:!1,hash:"2084b93f70df82e634ec776962e871fd",slug:"micromachining",bookSignature:"Zdravko Stanimirović and Ivanka Stanimirović",coverURL:"https://cdn.intechopen.com/books/images_new/7441.jpg",editedByType:"Edited by",editors:[{id:"3421",title:"Dr.",name:"Zdravko",middleName:null,surname:"Stanimirović",slug:"zdravko-stanimirovic",fullName:"Zdravko Stanimirović"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7454",title:"Industrial Engineering",subtitle:null,isOpenForSubmission:!1,hash:"7008bbdc804192f8969a34deda417b05",slug:"industrial-engineering",bookSignature:"Ainul Akmar Mokhtar and Masdi Muhammad",coverURL:"https://cdn.intechopen.com/books/images_new/7454.jpg",editedByType:"Edited by",editors:[{id:"219461",title:"Associate Prof.",name:"Ainul Akmar",middleName:null,surname:"Mokhtar",slug:"ainul-akmar-mokhtar",fullName:"Ainul Akmar Mokhtar"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7436",title:"New Trends in Industrial Automation",subtitle:null,isOpenForSubmission:!1,hash:"a6abb5722b5e27eb4b886a74f5aa4333",slug:"new-trends-in-industrial-automation",bookSignature:"Pengzhong Li",coverURL:"https://cdn.intechopen.com/books/images_new/7436.jpg",editedByType:"Edited by",editors:[{id:"19636",title:"Prof.",name:"Pengzhong",middleName:null,surname:"Li",slug:"pengzhong-li",fullName:"Pengzhong Li"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6838",title:"Power Plants in the Industry",subtitle:null,isOpenForSubmission:!1,hash:"5e647d27dab23e014dd8881ac3d5931c",slug:"power-plants-in-the-industry",bookSignature:"Tolga Taner",coverURL:"https://cdn.intechopen.com/books/images_new/6838.jpg",editedByType:"Edited by",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6332",title:"Thermal Power Plants",subtitle:"New Trends and Recent Developments",isOpenForSubmission:!1,hash:"616ffd286d75ca988abf59b408880a98",slug:"thermal-power-plants-new-trends-and-recent-developments",bookSignature:"Pawe? Madejski",coverURL:"https://cdn.intechopen.com/books/images_new/6332.jpg",editedByType:"Edited by",editors:[{id:"179645",title:"Dr.",name:"Paweł",middleName:null,surname:"Madejski",slug:"pawel-madejski",fullName:"Paweł Madejski"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"5830",title:"Extrusion of Metals, Polymers, and Food Products",subtitle:null,isOpenForSubmission:!1,hash:"a69184f72a3f46dd5e4db6313f248509",slug:"extrusion-of-metals-polymers-and-food-products",bookSignature:"Sayyad Zahid Qamar",coverURL:"https://cdn.intechopen.com/books/images_new/5830.jpg",editedByType:"Edited by",editors:[{id:"21687",title:"Dr.",name:"Sayyad Zahid",middleName:null,surname:"Qamar",slug:"sayyad-zahid-qamar",fullName:"Sayyad Zahid Qamar"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"5967",title:"Brewing Technology",subtitle:null,isOpenForSubmission:!1,hash:"033658c083403dadc895cf64dee8017a",slug:"brewing-technology",bookSignature:"Makoto Kanauchi",coverURL:"https://cdn.intechopen.com/books/images_new/5967.jpg",editedByType:"Edited by",editors:[{id:"85984",title:"Ph.D.",name:"Makoto",middleName:null,surname:"Kanauchi",slug:"makoto-kanauchi",fullName:"Makoto Kanauchi"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:48,mostCitedChapters:[{id:"15530",doi:"10.5772/14592",title:"Integrating Lean, Agile, Resilience and Green Paradigms in Supply Chain Management (LARG_SCM)",slug:"integrating-lean-agile-resilience-and-green-paradigms-in-supply-chain-management-larg-scm-",totalDownloads:5062,totalCrossrefCites:20,totalDimensionsCites:40,book:{slug:"supply-chain-management",title:"Supply Chain Management",fullTitle:"Supply Chain Management"},signatures:"Helena Carvalho and V. Cruz-Machado",authors:[{id:"18263",title:"Prof.",name:"Helena",middleName:null,surname:"Carvalho",slug:"helena-carvalho",fullName:"Helena Carvalho"},{id:"22440",title:"Prof.",name:"Virgílio",middleName:null,surname:"Cruz Machado",slug:"virgilio-cruz-machado",fullName:"Virgílio Cruz Machado"}]},{id:"17872",doi:"10.5772/19997",title:"Building Blocks of the Internet of Things: State of the Art and Beyond",slug:"building-blocks-of-the-internet-of-things-state-of-the-art-and-beyond",totalDownloads:4854,totalCrossrefCites:26,totalDimensionsCites:37,book:{slug:"deploying-rfid-challenges-solutions-and-open-issues",title:"Deploying RFID",fullTitle:"Deploying RFID - Challenges, Solutions, and Open Issues"},signatures:"Alexandru Serbanati, Carlo Maria Medaglia and Ugo Biader Ceipidor",authors:[{id:"37101",title:"Prof.",name:"Carlo Maria",middleName:null,surname:"Medaglia",slug:"carlo-maria-medaglia",fullName:"Carlo Maria Medaglia"},{id:"38529",title:"Prof.",name:"Ugo",middleName:null,surname:"Biader Ceipidor",slug:"ugo-biader-ceipidor",fullName:"Ugo Biader Ceipidor"},{id:"38530",title:"Mr.",name:"Alexandru",middleName:null,surname:"Serbanati",slug:"alexandru-serbanati",fullName:"Alexandru Serbanati"}]},{id:"34441",doi:"10.5772/35205",title:"Condition Monitoring of Railway Track Using In-Service Vehicle",slug:"condition-monitoring-of-railway-track-using-in-service-vehicle",totalDownloads:4634,totalCrossrefCites:17,totalDimensionsCites:33,book:{slug:"reliability-and-safety-in-railway",title:"Reliability and Safety in Railway",fullTitle:"Reliability and Safety in Railway"},signatures:"Hitoshi Tsunashima, Yasukuni Naganuma, Akira Matsumoto, Takeshi Mizuma and Hirotaka Mori",authors:[{id:"49517",title:"Prof.",name:"Hitoshi",middleName:null,surname:"Tsunashima",slug:"hitoshi-tsunashima",fullName:"Hitoshi Tsunashima"},{id:"113419",title:"Prof.",name:"Akira",middleName:null,surname:"Matsumoto",slug:"akira-matsumoto",fullName:"Akira Matsumoto"},{id:"113420",title:"Dr.",name:"Takeshi",middleName:null,surname:"Mizuma",slug:"takeshi-mizuma",fullName:"Takeshi Mizuma"},{id:"113422",title:"Mr.",name:"Hirotaka",middleName:null,surname:"Mori",slug:"hirotaka-mori",fullName:"Hirotaka Mori"},{id:"113423",title:"MSc.",name:"Yasukuni",middleName:null,surname:"Naganuma",slug:"yasukuni-naganuma",fullName:"Yasukuni Naganuma"}]}],mostDownloadedChaptersLast30Days:[{id:"51805",title:"Current Issues and Problems in the Joining of Ceramic to Metal",slug:"current-issues-and-problems-in-the-joining-of-ceramic-to-metal",totalDownloads:4086,totalCrossrefCites:6,totalDimensionsCites:14,book:{slug:"joining-technologies",title:"Joining Technologies",fullTitle:"Joining Technologies"},signatures:"Uday M.B., Ahmad-Fauzi M.N., Alias Mohd Noor and Srithar Rajoo",authors:[{id:"182041",title:null,name:"Uday",middleName:"M.",surname:"Basheer Al-Naib",slug:"uday-basheer-al-naib",fullName:"Uday Basheer Al-Naib"},{id:"182065",title:"Prof.",name:"Alias",middleName:null,surname:"Mohd Noor",slug:"alias-mohd-noor",fullName:"Alias Mohd Noor"},{id:"182066",title:"Dr.",name:"Srithar",middleName:null,surname:"Rajoo",slug:"srithar-rajoo",fullName:"Srithar Rajoo"},{id:"190437",title:"Prof.",name:"Ahmad-Fauzi",middleName:null,surname:"M. N.",slug:"ahmad-fauzi-m.-n.",fullName:"Ahmad-Fauzi M. N."}]},{id:"43383",title:"Improving Operations Performance with World Class Manufacturing Technique: A Case in Automotive Industry",slug:"improving-operations-performance-with-world-class-manufacturing-technique-a-case-in-automotive-indus",totalDownloads:25259,totalCrossrefCites:7,totalDimensionsCites:16,book:{slug:"operations-management",title:"Operations Management",fullTitle:"Operations Management"},signatures:"Fabio De Felice, Antonella Petrillo and Stanislao Monfreda",authors:[{id:"161682",title:"Prof.",name:"Fabio",middleName:null,surname:"De Felice",slug:"fabio-de-felice",fullName:"Fabio De Felice"},{id:"167280",title:"Dr.",name:"Stanislao",middleName:null,surname:"Monfreda",slug:"stanislao-monfreda",fullName:"Stanislao Monfreda"},{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}]},{id:"55749",title:"Exploitation of Brewing Industry Wastes to Produce Functional Ingredients",slug:"exploitation-of-brewing-industry-wastes-to-produce-functional-ingredients",totalDownloads:3099,totalCrossrefCites:7,totalDimensionsCites:16,book:{slug:"brewing-technology",title:"Brewing Technology",fullTitle:"Brewing Technology"},signatures:"Anca Corina Fărcaş, Sonia Ancuța Socaci, Elena Mudura, Francisc\nVasile Dulf, Dan C. Vodnar, Maria Tofană and Liana Claudia Salanță",authors:[{id:"191241",title:"Ph.D.",name:"Sonia A.",middleName:null,surname:"Socaci",slug:"sonia-a.-socaci",fullName:"Sonia A. Socaci"},{id:"191607",title:"Ph.D.",name:"Anca C.",middleName:null,surname:"Fărcaş",slug:"anca-c.-farcas",fullName:"Anca C. Fărcaş"},{id:"192098",title:"Prof.",name:"Maria",middleName:null,surname:"Tofana",slug:"maria-tofana",fullName:"Maria Tofana"},{id:"192177",title:"Dr.",name:"Dan Cristian",middleName:null,surname:"Vodnar",slug:"dan-cristian-vodnar",fullName:"Dan Cristian Vodnar"},{id:"194168",title:"Dr.",name:"Francisc Vasile",middleName:null,surname:"Dulf",slug:"francisc-vasile-dulf",fullName:"Francisc Vasile Dulf"},{id:"203096",title:"Dr.",name:"Elena",middleName:null,surname:"Mudura",slug:"elena-mudura",fullName:"Elena Mudura"},{id:"203097",title:"Dr.",name:"Liana Claudia",middleName:null,surname:"Salanta",slug:"liana-claudia-salanta",fullName:"Liana Claudia Salanta"}]},{id:"53519",title:"Understanding the Stakeholders as a Success Factor for Effective Occupational Health Care",slug:"understanding-the-stakeholders-as-a-success-factor-for-effective-occupational-health-care",totalDownloads:1781,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"occupational-health",title:"Occupational Health",fullTitle:"Occupational Health"},signatures:"Ari-Matti Auvinen",authors:[{id:"193252",title:"M.A.",name:"Ari-Matti",middleName:null,surname:"Auvinen",slug:"ari-matti-auvinen",fullName:"Ari-Matti Auvinen"}]},{id:"43001",title:"Production Scheduling Approaches for Operations Management",slug:"production-scheduling-approaches-for-operations-management",totalDownloads:5934,totalCrossrefCites:1,totalDimensionsCites:5,book:{slug:"operations-management",title:"Operations Management",fullTitle:"Operations Management"},signatures:"Marcello Fera, Fabio Fruggiero, Alfredo Lambiase, Giada Martino and Maria Elena Nenni",authors:[{id:"163046",title:"Dr.",name:"Fabio",middleName:null,surname:"Fruggiero",slug:"fabio-fruggiero",fullName:"Fabio Fruggiero"}]},{id:"43436",title:"The Important Role of Packaging in Operations Management",slug:"the-important-role-of-packaging-in-operations-management",totalDownloads:6781,totalCrossrefCites:4,totalDimensionsCites:7,book:{slug:"operations-management",title:"Operations Management",fullTitle:"Operations Management"},signatures:"Alberto Regattieri and Giulia Santarelli",authors:[{id:"72034",title:"Prof.",name:"Alberto",middleName:null,surname:"Regattieri",slug:"alberto-regattieri",fullName:"Alberto Regattieri"}]},{id:"65164",title:"Maintenance Management of Aging Oil and Gas Facilities",slug:"maintenance-management-of-aging-oil-and-gas-facilities",totalDownloads:1343,totalCrossrefCites:1,totalDimensionsCites:2,book:{slug:"maintenance-management",title:"Maintenance Management",fullTitle:"Maintenance Management"},signatures:"Riaz Khan, Ammeran B. Mad, Khairil Osman and Mohd Asyraf Abd Aziz",authors:[{id:"215673",title:"Dr.",name:"Riaz",middleName:null,surname:"Khan",slug:"riaz-khan",fullName:"Riaz Khan"},{id:"277895",title:"Dr.",name:"Ammeran B.",middleName:null,surname:"Mad",slug:"ammeran-b.-mad",fullName:"Ammeran B. Mad"},{id:"277897",title:"Dr.",name:"Khairil",middleName:null,surname:"Osman",slug:"khairil-osman",fullName:"Khairil Osman"},{id:"277898",title:"Dr.",name:"Mohd Asyraf",middleName:null,surname:"Abdul Aziz",slug:"mohd-asyraf-abdul-aziz",fullName:"Mohd Asyraf Abdul Aziz"}]},{id:"43375",title:"Product Sound Design: Intentional and Consequential Sounds",slug:"product-sound-design-intentional-and-consequential-sounds",totalDownloads:2866,totalCrossrefCites:15,totalDimensionsCites:25,book:{slug:"advances-in-industrial-design-engineering",title:"Advances in Industrial Design Engineering",fullTitle:"Advances in Industrial Design Engineering"},signatures:"Lau Langeveld, René van Egmond, Reinier Jansen and Elif Özcan",authors:[{id:"39586",title:"MSc.",name:"Lau",middleName:null,surname:"Langeveld",slug:"lau-langeveld",fullName:"Lau Langeveld"},{id:"156849",title:"MSc.",name:"Reinier",middleName:null,surname:"Jansen",slug:"reinier-jansen",fullName:"Reinier Jansen"},{id:"156854",title:"Dr.",name:"Rene",middleName:null,surname:"Van Egmond",slug:"rene-van-egmond",fullName:"Rene Van Egmond"},{id:"156855",title:"Dr.",name:"Elif",middleName:null,surname:"Ozcan",slug:"elif-ozcan",fullName:"Elif Ozcan"}]},{id:"54655",title:"Key Technical Performance Indicators for Power Plants",slug:"key-technical-performance-indicators-for-power-plants",totalDownloads:2424,totalCrossrefCites:0,totalDimensionsCites:1,book:{slug:"recent-improvements-of-power-plants-management-and-technology",title:"Recent Improvements of Power Plants Management and Technology",fullTitle:"Recent Improvements of Power Plants Management and Technology"},signatures:"Simona Vasilica Oprea and Adela Bâra",authors:[{id:"139804",title:"Prof.",name:"Adela",middleName:null,surname:"Bara",slug:"adela-bara",fullName:"Adela Bara"},{id:"188586",title:"Dr.",name:"Simona Vasilica",middleName:null,surname:"Oprea",slug:"simona-vasilica-oprea",fullName:"Simona Vasilica Oprea"}]},{id:"55197",title:"Changes in Nutritional Properties and Bioactive Compounds in Cereals During Extrusion Cooking",slug:"changes-in-nutritional-properties-and-bioactive-compounds-in-cereals-during-extrusion-cooking",totalDownloads:1052,totalCrossrefCites:3,totalDimensionsCites:4,book:{slug:"extrusion-of-metals-polymers-and-food-products",title:"Extrusion of Metals, Polymers, and Food Products",fullTitle:"Extrusion of Metals, Polymers and Food Products"},signatures:"Cuauhtémoc Reyes Moreno, Perla C. Reyes Fernández, Edith O.\nCuevas Rodríguez, Jorge Milán Carrillo and Saraid Mora Rochín",authors:[{id:"198302",title:"Dr.",name:"Saraid",middleName:null,surname:"Mora-Rochín",slug:"saraid-mora-rochin",fullName:"Saraid Mora-Rochín"},{id:"199537",title:"Dr.",name:"Perla C.",middleName:null,surname:"Reyes Fernández",slug:"perla-c.-reyes-fernandez",fullName:"Perla C. Reyes Fernández"},{id:"199538",title:"Dr.",name:"Edith O.",middleName:null,surname:"Cuevas Rodríguez",slug:"edith-o.-cuevas-rodriguez",fullName:"Edith O. Cuevas Rodríguez"},{id:"199539",title:"Dr.",name:"Cuauhtémoc",middleName:null,surname:"Reyes Moreno",slug:"cuauhtemoc-reyes-moreno",fullName:"Cuauhtémoc Reyes Moreno"},{id:"199540",title:"Dr.",name:"Jorge",middleName:null,surname:"Milán Carrillo",slug:"jorge-milan-carrillo",fullName:"Jorge Milán Carrillo"}]}],onlineFirstChaptersFilter:{topicSlug:"industrial-engineering-and-management",limit:3,offset:0},onlineFirstChaptersCollection:[],onlineFirstChaptersTotal:0},preDownload:{success:null,errors:{}},aboutIntechopen:{},privacyPolicy:{},peerReviewing:{},howOpenAccessPublishingWithIntechopenWorks:{},sponsorshipBooks:{sponsorshipBooks:[{type:"book",id:"10176",title:"Microgrids and Local Energy Systems",subtitle:null,isOpenForSubmission:!0,hash:"c32b4a5351a88f263074b0d0ca813a9c",slug:null,bookSignature:"Prof. Nick Jenkins",coverURL:"https://cdn.intechopen.com/books/images_new/10176.jpg",editedByType:null,editors:[{id:"55219",title:"Prof.",name:"Nick",middleName:null,surname:"Jenkins",slug:"nick-jenkins",fullName:"Nick Jenkins"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:8,limit:8,total:1},route:{name:"profile.detail",path:"/profiles/188597/diego-leite-da-cunha",hash:"",query:{},params:{id:"188597",slug:"diego-leite-da-cunha"},fullPath:"/profiles/188597/diego-leite-da-cunha",meta:{},from:{name:null,path:"/",hash:"",query:{},params:{},fullPath:"/",meta:{}}}},function(){var e;(e=document.currentScript||document.scripts[document.scripts.length-1]).parentNode.removeChild(e)}()