Study of mixed ligand copper( I) complexes with tri- m-tolyl-phosphine (tmtp) and heterocyclic thiones. Crystal structures of bis[μ-S(benzimidazoline-2-thione)(tmtp) copper( I) chloride] and bis[μ-Br(thiazolidine-2-thione)(tmtp) copper( I)

Abstract

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 1H NMR spectroscopic data. The photolysis of these complexes in dichloromethane solutions has been investigated. The crystal structures of [Cu(tmtp)(bzimtH 2)Cl] 2 ( I) 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) Å, β=102.76(3)°, D calc=1.421(1) Mg m −3, V=2586.5(3) Å 3 and Z=2 for [Cu(tmtp)(bzimtH 2)Cl] 2 and space group P2 1/ n with a=15.085(1), b=9.820(3), c=17.263(1) Å, β=99.77(3)°, D calc=1.494 Mg m −3, V=2520.2(4) Å 3 and Z=2 for [Cu(tmtp)- (thzdtH)Br] 2. The chloro complex contains a planar Cu 2S 2 moiety with CuS bond lengths of 2.386(2) and 2.444(1) Å and CuP and CuCl distances equal to 2.251(1) and 2.391(2) Å, respectively. The Cu···Cu separation is 2.764(1) Å. The bromo molecule forms a planar Cu 2Br 2 frame with CuBr bond lengths of 2.5182(2) and 2.5971(8) Å and CuP and CuS distances equal to 2.240(1) and 2.307(1) Å, respectively. The Cu···Cu separation is 3.3471(7) Å. Rationalization of the above described properties in terms of stereoelectronic factors governing bond formation is attempted by means of EHT computations.