Sulphur ligand–metal complexes. Part 16. Copper complexes of thioethers and the single-crystal X-ray structure of the polymeric mixed-valence complex, penta-µ-chloro-tris-µ-tetrahydrothiophene-tetracopper(I,II)
Abstract
The interaction of the cyclic, thioether ligand, L1(tetrahydrothiophene), with CuCl2·2H2O in acetone yields the polymeric, mixed-valence complex [{CuI3CuIIL13Cl5}n], the crystal and molecular structure of which has been determined by X-ray diffraction techniques. Crystals of the complex are monoclinic, space group P21/n, with a= 12.2288(6), b= 13.0277(7), c= 14.0605(7). Å, β= 95.815(4)°, and Z= 4. The structure was solved by direct methods and Fourier-difference techniques, and refined by block-diagonal least squares to R= 0.029 for 2 770 observed intensities. The structure is polymeric with µ-Cl or µ-L1 linkages between Cu atoms giving rise to three different ring systems, viz.[Cu(µ-Cl)]2 and [Cu(µ-L1)]3 fused to [Cu(µ-L1){Cu(µ-Cl)}2]. The copper atoms designated as CuII are bound to four chlorine atoms to give a geometry intermediate between tetrahedral and square planar, and those designated as CuI have distorted tetrahedral S2Cl2 donor sets. This complex, if left in its mother-liquor, forms the oxidised thioether ligand complex [{Cu(L1O)Cl2}n](L1O = tetrahydrothiophene 1-oxide). Other cyclic thioethers, L2(thiacyclohexane) and L3(1,3-dithiacyclopentane), from either copper(I) or copper(II) complexes: [CuLX](L = L1 or L3, X = Cl or Br; L = L2, X = Cl), [(CuCl)3L12], [CuL32]ClO4·2H2O, and [CuL3Cl2]. The bidentate thioethers L4(2,2,7,7-tetramethyl-3,6-dithiaoctane), L5(3,8-dithiadecane), L6(2,9-dithiadecane), and L8[3,4-di(methylthio)toluene] yield the complexes: [CuLX](L = L4, X = Cl or Br), [(CuX)2L](L = L4 or L5; X = Cl, Br, or I), [CuL2]BF4(L = L4 or L5), [(CuCl2)2L4], [CuL4(NO3)2]·H2O, [(CuX)3L62](X = Cl, Br or I), and [CuL8Cl2]. The ligand L7(tetradecylthioacetate ion) forms the copper(II) complex [CuL72]·2H2O. These complexes have been characterised by a variety of spectroscopic techniques and, where possible, structures are proposed.