Studies on dithio- o-toluate copper(I) complexes with bis(diphenylphosphino)methane. Crystal structures of {di-μ 3-dithio- o-toluato-S,S′,S′-bis[μ-bis(diphenylphosphino)methane-μ-dithio- o-toluato-S,S′]} tetracopper(I) and {di[μ-bis(diphenylphosphino)methane]bis(dithio- o-toluato-S,S′)} dicopper(I)

Abstract

The structures of [(CuS 2CT) 2dppm] 2 ( I) (T = o-tolyl; dppm = bis(diphenylphosphino)methane) and [CuS 2CTdppm] 2 ( II) have been determined by X-ray methods. Crystals of I are monoclinic, space group P2 1/ n, with a = 15.163(4), b = 18.691(5), c = 13.478(4) Å, β = 96.81(3)°, Z = 2; crystals of II are orthorhombic. space group Pccn, with a = 23.267(4), b = 13.016(3), c = 20.731(5) Å, Z = 4. The structures of I and II have been solved by Patterson and Fourier methods and refined by full-matrix least-squares to R = 0.082 for I and 0.092 for II. The structure of I consists of centrosymmetric tetranuclear complexes in which two pairs of Cu atoms are triply bridged by a dppm ligand and two dithiocarboxylate groups from the dithio- o-toluate ligands. These last behave differently: one of them through a sulphur atom is also bonded to a Cu atom of the other pair so forming a tetranuclear complex. The Cu atoms of each pair show different coordination: Cu(1) displays a distorted trigonal and Cu(2) a distorted trigonal pyramidal geometry. The structure of II consists of dimers, in which each copper atom, doubly bridged by two dppm ligands, completes a distorted trigonal pyramidal coordination through two sulphur atoms from dithio- o-toluate anions acting as chelating ligands. In both compounds the phenyl group of the dithio- o-toluate anions is orthogonal to the corresponding CS 2 group. Both complexes give methyldithio- o-toluate in high yields by reaction with methyl iodide.