Heterobimetallic aggregates of copper(I) with thio-tungstate and -molybdate. Cation effect in aggregation of MS4Cu4Cl4 units, a crystallographic study

Abstract

Reaction of [MS₄]^2–(M = Mo or W) with CuCl in dichloromethane or acetonitrile gives a new set of bimetallic compounds isolated with various geometries for the same 1:4:4 M:S:Cu composition. Crystals of [NBu₄]₂[MoS₄Cu₄Cl₄]1a are tetragonal, space group I/m, a= 13.343(5), c= 14.113(2)Å, Z= 2, R= 0.058. The crystal structure reveals discrete [MoS₄Cu₄Cl₄]^2– anions separated in the lattice by [NBu₄]⁺ cations. The isostructural tungsten homologue 1b was isolated and characterized: space group I/m, tetragonal, a= 13.342(4), c= 14.106(5)Å. The structure of [PPh₄][NPr₄][MoS₄Cu₄Cl₄]2 consists of a dimeric aggregate: monoclinic, space group P2₁/n, a= 9.962(8), b= 36.951(5), c= 13.114(3)Å, β= 105.71(6)°, R= 0.056. The salt [NPr₄]₂[WS₄Cu₄Cl₄]3b is polymerized through linear chains. Crystals are triclinic, space group P, a= 10.283(1), b= 13.925(1), c= 15.245(1)Å, α= 110.32(1), β= 90.64(1), γ= 102.49(1)°, Z= 2, R= 0.031. The isostructural molybdenum compound 3a was also characterized: triclinic, a= 10.275, b= 13.961, c= 15.270 Å, α= 110.57, β= 90.70, γ= 102.30°. The arrangements of the mono-, di- and poly-meric aggregates in the lattice are discussed in terms of the size of the counter anion. For compounds 1b and 3a only the cell dimensions were determined.