Spectroelectrochemical Studies and Axial Ligation Effect on Visible Absorption Spectra of Some Heme Manganese Complexes

Abstract

Abstract Effect of the axial ligand on the visible absorption spectra of Mn(III)[T(4 – CH3 P)P]Cl, Mn(III)[T(4 – Cl P)P]Cl and Mn(III)[T(4 – CH3 P)P]Cl in non-coordinating solvent like CH2Cl2 have been investigated. Exchange of the axial ligand (-Cl) with amines and the coordination of amine as the sixth ligand are discussed. Blue shift in the Soret band has been attributed to the change in the conformation of the porphyrin. Cyclic voltammograms (at room temperature) in non-ligating solvent (CH2Cl2) with two redox couples are observed. Spectroelectrochemical experiments also exhibits blue shifts highlighting the differences in HOMO – LUMO energy gap of the metalloporphyrins; characteristic absorption at 420nm of MnIV porphyrin is reported.