Synthesis, X-ray crystal structure and DFT calculations of bis(N-(2-picolyl) picolinamido) Mn(III) hexafluorophosphate

A Mn(III) complex [Mn(pmpa)(2)](PF6) (pmpaH = N-( 2-picolyl)picolinamide) has been synthesized and structurally characterized by X-ray crystallography. The complex undergoes one electron oxidation and reduction at 1.05 V and -0.20 V ( versus Ag/AgCl electrode) respectively. DFT calculations show that both redox processes have significant ligand character. DFT calculations also show that there is strong electronic coupling between the central metal ion and the amide ligands, which leads to higher ligand-to-metal charge transfer and thus higher metal-ligand covalency with increasing oxidation state on the central metal ion. This implies that amide ligands are redox non-innocent.