A double helical dicopper(II) complex with biacetyl bis(benzoylhydrazone)

A dinuclear double helicate of copper(II) with the Schiff base biacetyl bis(benzoylhydrazone) (H2babh) is reported. The solid state physical properties of the dicopper(II) species are compared with that of its mononuclear precursor. The O,N,N,O-donor babh2− shows an unusual bridging coordination mode in [Cu2(μ-babh)2]. Each metal center in the complex is in very similar tetrahedrally distorted square-planar N2O2 coordination sphere assembled by the two halves of the two babh2−. To accommodate the metal centers, two halves of each ligand are twisted along the (CH3)C–C(CH3) bond.