THE DIRECT ELECTROCHEMICAL SYNTHESIS OF THE NOVEL COPPER(I) COMPLEX CU2[OC6CL4(OH)]2[(C6H5)2PCH2P(C6H5)2]2

The electrochemical oxidation of copper in an acetonitrile solution of an aromatic diol (R(OH)2 = catechol, tetrachloro-1,2-dihydroxybenzene, 2,2'-dihydroxybiphenyl) gives soluble copper(I) products which are reduced to copper at a platinum cathode. In the presence of R(OH)2 + L (L = 2,2'-bipyridine, triphenylphosphine, bis(diphenylphosphino)methane (= dppm)), the products are adducts of copper(I) species in which the anionic ligand is [R(O)OH]-. The crystal structure of Cu2[OC6Cl4(OH)]2-(dppm)2 is triclinic, with a = 22.418(5) angstrom, b = 11.784(4) angstrom, c = 13.492(4) angstrom, alpha = 61.63(2)-degrees, beta = 86.66(2)-degrees, gamma = 80.61(2), V = 3093(2) angstrom 3, Z = 2, and space group P1. The molecule consists of a Cu-P-C-P-Cu-P-C-P ring, with copper ligated by [R(O)OH]- groups external to this. Intramolecular O-H---O hydrogen-bonding contributes to the stabilization of this novel complex.