ABSTRACT
A metal cation in metalloporphyrins (MPs) has an effective positive charge; therefore, it can bond both positively and negatively charged ligands in the axial direction of a molecule.1-3 In other words, a metal porphyrin coordinative capacity is not exhausted by the formation of simple metalporphyrin complexes. A mixed complex formation is represented as one of the most important properties of this class of compounds and is of great theoretical and practical interest due to necessity to study porphyrin biological functions and to elaborate anion and molecule receptors. The thermodynamics of oxygen/nitrogen ligand coordination with M2+ porphyrin complexes has been already studied for a long time.4-7 The porphyrin complexes of highly charged (z > 2) p-and d-metal cations show higher sensitivity to the action of the organic bases such as hydrogen sulde, imidazole, and pyridine in the inert solvents.8-19 Axial complexes of metal porphyrins with organic bases have a donor-acceptor nature.
