Aleksey Kuznetsov

By Aleksey E. Kuznetsov

Metalloporphyrins and related macrocycles have been of great interest due to their role in biology and their numerous technological applications. Engineering of the porphyrins by replacing pyrrole nitrogens with other elements is a highly promising approach for tuning properties of porphyrins. To date, numerous efforts have been made to the modification of the porphyrin core with main‐group elements, such as chalcogens (O, S, Se) and phosphorus. Thus, the modification of the porphyrin core by incorporation of heteroatoms instead of nitrogens is a very promising strategy for obtaining novel compounds with unusual optical, electrochemical and coordinating properties as well as reactivity. These novel compounds can be used as building blocks in various nanotechnological applications. Within the framework of this research, the following questions can be formulated: (i) what structures will core‐modified porphyrins adopt? (ii) How will electronic properties of core‐modified porphyrins differ from those of common tetrapyrroles? (iii) Will the core‐modified porphyrins be able to form stacks and other arrays like regular porphyrins? (iv) Can core‐modified porphyrins form complexes with fullerenes? (v) Can core‐modified porphyrins activate small molecules, e.g. O2 or N2? (vi) Will the core‐modified porphyrins be able to form complexes with nanoparticles?

Part of the book: Descriptive Inorganic Chemistry Researches of Metal Compounds

By Aleksey E. Kuznetsov

Part of the book: Azoles

By Akbar Ali, Aleksey Kuznetsov, Muhammad Ibrahim, Azhar Abbas, Nadia Akram, Tahir Maqbool and Ushna

Co-crystals are multicomponent molecular materials held together through non-covalent interactions that have recently attracted the attention of supramolecular scientists. They are the monophasic homogeneous materials where a naturally occurring pharmaceutical active ingredient (API) and a pharmaceutically acceptable co-crystal former are bonded together in a 1:1 via non-covalent forces such as H-bonds, π–π, and van der Waals forces. Co-crystallization is a promising research field, especially for the pharmaceutical industry, due to the enormous potential of improved solubility and bioavailability. Co-crystals are not the only multicomponent molecular materials, as there are many other forms of multicomponent molecular solids such as salts, hydrates, solvates, and eutectics. The formation of co-crystals can roughly be predicted by the value of ∆pKa, that is, if the ∆pKa is more than 3, then this monophasic homogeneous material usually falls in the category of salts, whereas if the ∆pKa is less than 2, then co-crystals are usually observed. A number of methods are available for the co-crystal formation, broadly classified into two classes established on state of formation, that is, solution-based and solid-based co-crystal formation. Similarly, a number of techniques are available for the characterization of co-crystals such as Fourier transforms-infrared spectroscopy, single-crystal and powder X-ray diffraction, etc. In this chapter, we will discuss the available methods for co-crystallization and its characterization.

Part of the book: Drug Formulation Design