THE COPPER PROMOTED OXIDATION OF 1-METHYLIMIDAZOLINE-2(3H)-THIONE TO BIS(1-METHYLIMIDAZOL-2-YL)SULFIDE

The interaction of 1-methylimidazoline-2(3H)-thione (HL1) in nitromethane solution with copper(II) perchlorate or nitrate yields the complexes [Cu(L2)2(H2O)2]X2.nH2O (X- = ClO4-, n = 2; X- = NO3-, n = 0) where L2 is the chelate N-donor ligand bis(1-methylimidazol-2-yl)sulfide. The single crystal structure of the complex [Cu(L2)2(H2O)2](ClO4)2.2H2O has been determined. Crystals of the complex are monoclinic, space group P2(1)/n with a = 7.696(2), b = 13.875(3), c = 13.186(2) angstrom, beta = 95.98(2)-degrees and Z = 2. The coordination around the copper is approximately tetragonal with the imino nitrogen atoms from the L2 ligands equatorial (Cu-N 1.990(3) and 2.004(3) angstrom) and the water molecules axial (Cu-O 2.501(4) angstrom). Evidence presented, indicates that the sulfur extruded from the coupling of two HL1 molecules, during the formation of L2, is ultimately oxidised to the sulfate ion.