Structure and bonding in the hydrothermally synthesized copper(I) complex Cu4(μ2-Cl)4(BIPY)2

The title compound corresponds to a molecular product of the hydrothermal reaction of CuCl2, Zn, and BIPY (BIPY=2,2′-bipyridine) in the presence of phosphoric acid. The structure of the neutral complex Cu4(μ2-Cl)4(BIPY)2 determined by means of X-ray diffraction consists of molecular units constructed around a Cu4 parallelogram, with diagonally opposed tetrahedral and linear copper centers. DFT calculations provide a rationalization of the bonding in this molecule.