Synthesis and electrochemical properties of binuclear molybdenum carbonyl complexes with bridging α,α′-diimine ligands

Abstract

New binuclear molybdenum complexes with bridging ligands derived from 2-pyridinecarbaldehyde and the diamines such as hydrazine, p-phenylenediamine, p-xylylenediamine, and 4,4′-diaminobiphenyl were prepared, to elucidate the effect on the separated distance and π-conjugation between two metal centers. All the complexes exhibit the low lying metal-to-ligand charge transfer (MLCT) bands at ca. 500 nm. The cyclic voltammogram shows either a single broad two-electron wave, or two one-electron reduction waves, depending on the nature of the bridging ligand. The MLCT band and the reduction behavior are rationalized in terms of the interaction between LUMO orbitals of two molybdenum-α,α′-diimine moieties.