Metal-heterocyclic thione interactions.: 13.: Pyridine-2-thione derivatives of copper(I):: crystal structure of dinuclear [bromo(pyridine-2-thione)(tri-p-tolylphosphine)copper(I)]2 complex

The sulfur-bridged dinuclear copper (1) complex, [CuBr(eta(2)-S-mu-C5H5NS)(p-Tol(3)P)](2) (1) was prepared by the reaction of insoluble CuBr2(C5H5NS)(2) {from copper(II) bromide and pyridine-2-thione(C5H5NS) in ethanol} with excess tri-p-tolylphosphine (p-Tol(3)P) in chloroform (1:2 mole ratio). Similarly, other copper(l) complexes of stoichiometry [CuX(C5H5NS)(Ph3P)](2) {X = Cl, 2 and 1, 3 were prepared. Compound I crystallised from a dichloromethane-chloroform-methanol mixture and exists as a centrosymmetric sulfur-bridged dimer with distorted tetrahedral geometry about each Cu atom the other two positions of each Cu atom being occupied by a P atom from p-Tol(3)P and a bromine atom. The central core Cu2S2 of the dimer is a parallelogram with the important interatomic parameters as follows: Cu-P, 2.2376(13), Cu-S, 2.3895(19), 2.415(2), Cu-Br, 2.4455(l 1), S-C(2), 1.717(4), Cu-Cu*, 3.250(2), S-S*, 3.539(3) Angstrom; Cu-S-Cu*, 85.14(6), S-Cu-S*, 94.86(6), Cu-S-C(2). 108.41(14), 113.12(16)degrees. The dimer structure is stabilised by strong intramolecular N-H...Br hydrogen bonds [3.319(5) Angstrom]. The X-ray Study of 2 showed that it has transformed into monomer [CuCl(eta(1)-S-mu-C5H5NS)(Ph3P)(2)] (4) during crystal growth. The strong intramolecular N-H...Cl hydrogen bonding appears to stabilise the monomer. All the Compounds were characterised using analytical data, IR and far-IR (4000-100 cm(-1)), UV-Vis spectra, NMR (H-1, C-13) and for I and 4 using X-ray crystallography. The factors controlling Cu...Cu interaction in the sulfur-bridged dinuclear copper(l)-heterocyclic thione complexes are described. (C) 2002 Elsevier Science Ltd. All rights reserved.