Metal–metal communication in diruthenium complexes of the bridging ligand bis(imidazo[4,5-f][1,10]phenanthroline)

A series of diruthenium complexes incorporating bis(imidazo[4,5-f][1,10]phenanthroline) bridging structures were synthesized and their electrochemical properties were investigated. Upon changing the ancillary ligands of one diruthenium complex from 2,2′-bipyridine (bpy) to 1,10-phenanthroline (phen), electrochemical experiments revealed behavior that suggested through-bridge, metal-to-metal communication. By changing the inductive properties of the bridging ligand, the degree of communication could be controlled. The results point toward a hole-type superexchange electron transport mechanism.