Genuine redox isomerism in a rare-earth-metal complex

Abstract

Redox isomerism is observed for a lanthanide complex for the first time. Upon lowering the temperature, an electron of [{(dpp-bian)Yb(μ-Cl)(dme)}(2)] (1) is transferred from the metal to the ligand (see picture), giving rise to marked shortening of Yb-N bonds and a hysteretic jump in the magnetic moment. The crystal packing is of a crucial importance, as two other crystal modifications of 1 do not undergo this effect.