Effects of SbCl5, Ethylamine, Imidazole and 2-Methylimidazole on Redox and Structural Behaviours of Manganese(III) meso-5,10,15,20-tetrakis(4-pyridyl)porphyrin

Abstract

A porphyrin compound manganese(III) meso-5,10,15,20-tetrakis(4-pyridyl)porphyrin, Mn(Py)4P containing manganese(III) and 4-pyridyl ligands was synthesized. The UV-visible spectrophotometry and cyclic voltammetry were used to investigate the axial ligand and the redox behaviours of Mn(Py)4P. This study investigates the reduction properties of Mn(Py)4P using primary amine, imidazole and 2-methylimidazole as axial ligands. Reduction of Mn(Py)4P leads to a shift in absorption bands, indicating the conversion from manganese(III) to manganese(II) porphyrin. The addition of primary amine results in a square pyramidal structure for Mn(II) porphyrin, while imidazole or 2-methylimidazole leads to the formation of tetragonal complexes. These changes in geometry result in a decrease in π-bonding. The observed spectral patterns support the involvement of axial ligands in the 5th and 6th positions of manganese(III) porphyrin. The cyclic voltammogram confirmed the alteration in geometry, indicating changes in the redox properties of compound. As a whole, the results of this study provide light on the ways where the behaviour of in which Mn(Py)4P can be altered by the presence of other molecules.