Polynuclear Cu₄L₄ Copper(II) Aminyl Radical Coordination Complexes

We describe the structural features and magnetic properties of two polynuclear copper­(II) complexes containing a redox-active ligand. These neutral complexes each bear the formula RL₄Cu₄ (R = ^tBu, Me) with the ligand in a dianion-aminyl radical oxidation state. X-ray data and density functional theory calculations support an aminyl-type radical character in these complexes, making these the first polynuclear metal aminyl radical complexes.