STUDY OF MIXED-LIGAND COPPER(I) COMPLEXES WITH TRI-META-TOLYL-PHOSPHINE (TMTP) AND HETEROCYCLIC THIONES - CRYSTAL-STRUCTURES OF BIS[MU-S(BENZIMIDAZOLINE-2-THIONE)(TMTP) COPPER(I) CHLORIDE] AND BIS[MU-BR(THIAZOLIDINE-2-THIONE)(TMTP) COPPER(I)]

Reactions of [Cu(tmtp)X]n (tmtp = tri-m-tolyl-phosphine; X = Cl, Br) with heterocyclic thiones (L) (L = pyridine-2-thione(py2SH), pyrimidine-2-thione (pymtH), 1,3-thiazolidine-2-thione (tzdtH), 1-methyl-1,3-imidazoline-2-thione (meimtH), benz-1,3-imidazoline-2-thione (bzimtH-2) and quinoline-2-thione (qntH)) yield binuclear complexes of the general formula [Cu(tmtp)(L)X]2. The complexes have been characterized by elemental analyses and their IR, UV-Vis and H-1 NMR spectroscopic data. The photolysis of these complexes in dichloromethane solutions has been investigated. The crystal structures of [Cu(tmtp)(bzimtH2)Cl]2 (1) and [Cu(tmtp)(tzdtH)Br]2 (II) have been determined by single-crystal X-ray diffraction methods. The white crystals of the two compounds are both monoclinic, space group P2(1)/a with a = 12.636(8), b = 15.325(6), c = 13.696(8) angstrom, beta = 102.76(3)-degrees, D(calc) = 1.421(1) Mg m-3, V = 2586.5(3) angstrom3 and Z = 2 for [Cu(tmtp)(bzimtH2)Cl]2 and space group P2(1)/n with a = 15.085(1), b = 9.820(3), c = 17.263(1) angstrom, beta = 99.77(3)-degrees, D(calc) = 1.494 Mg m-3, V = 2520.2(4) angstrom3 and Z = 2 for [Cu(tmtp)(thzdtH)Br]2. The chloro complex contains a planar Cu2S2 moiety with Cu-S bond lengths of 2.386(2) and 2.444(l) angstrom and Cu-P and Cu-C] distances equal to 2.251(l) and 2.391(2) angstrom, respectively. The Cu...Cu separation is 2.764(l) angstrom. The bromo molecule forms a planar CU2Br2 frame with Cu-Br bond lengths of 2.5182(2) and 2.5971(8) angstrom and Cu-P and Cu-S distances equal to 2.240(l) and 2.307(l) angstrom, respectively. The Cu...Cu separation is 3.3471(7) angstrom. Rationalization of the above described properties in terms of stereoelectronic factors governing bond formation is attempted by means of EHT computations.