The Hepta(μ-benzenethiolato)pentametallate(I) dianions of copper and silver: Formation and crystal structures

Abstract

The yellow complexes (Me₄N)₂Cu₅(SPh)₇ and (Me₄N)₂Ag₅(SPh)₇, soluble in aprotic solvents, have been synthesized. Crystal structure results are: (Me₄N)₂Cu₅(SPh)₇, a 12.250(1), b 20.151(4), c 11.531(2) Ǻ, α 103.50(1), β 90.01(1), γ 83.20(1), space group Pī, Z 2, 3639 reflections (Mo Kα), full anisotropic refinement, R 0.051; (Me₄N)₂Ag₅(SPh)₇, a 12.393(1), b 20.633(4), c 11.674(1) Ǻ α 103.88(1), β 90.35(1), γ 82.96(1)°, space group Pī, Z 2, 6400 reflections (Mo Kα), full anisotropic refinement, R 0.030. The crystals are isostructural.    

The crystals contain a molecular cluster [M₅(SPh)₇]^2-, the structure of which may be visualized in terms of the array of metal atoms which is formed by addition of a unique fifth metal atom over one elongated edge of an approximate tetrahedron of metal atoms. Benzene thiolate ligands bridge the seven edges of the resulting polyhedron of metal atoms. The four metal atoms derived from the tetrahedron possess approximately trigonal planar coordination, while the unique metal atom has approximately linear (S-M-S 175.2° (Cu), 176.0° (Ag)) digonal coordination. There is no evidence of strong metal-metal bonding in the M₅S₇ core, which has very approximate C_2v symmetry. Average bond lengths are Cu_dig-S, 2.160; Cu_trig-S, 2.270; Ag_dig-S, 2.361; Ag_trig-S, 2.502 Ǻ.