ELECTRON-TRANSFER AND LIGAND-ADDITION REACTIONS OF (MESO-TETRAPHENYLPORPHINATO)MANGANESE(II) AND (MESO-TETRAPHENYLPORPHINATO)MANGANESE(III) CHLORIDE

The electron-transfer and ligand-addition reactions of (meso-tetraphenylporphinato)manganese(II) and -manganese(III) chloride were investigated by polarography and cyclic voltammetry in dichloromethane. A mechanism of electron transfer was proposed in both the presence and absence of nitrogenous base. Formation constants for binding of six different substituted pyridines by Mn(II) and Mn(III) were calculated. Under the experimental conditions only five-coordinate complexes existed in solution. Binding of the substituted pyridine to (TPP)MnCl produced the complex [(TPP)MnL]+ rather than (TPP)Mn(L)(Cl). In all cases K1 for (TPP)MnL formation was greater than that for [(TPP)MnL]+. A linear correlation between the log of the formation constant of the pentacoordinate complex and the pKa of the added ligand was found. © 1979, American Chemical Society. All rights reserved.