Contributions to the chemistry of silicon-sulphur compounds—LX. Synthesis, molecular structure and properties of the dimeric cadmium(II) bis(tri-tert-butoxysilanethiolate) (t-C 4H 9O) 3SiS 2Cd 2

Abstract

The preparation and X-ray crystal structure of cadmium(II) bis(tri-tert-butoxysilanethiolate) from tri-tert-butoxysilanethiol and cadmium acetate are described. The compound forms a dimeric molecule (t-C 4H 9O) 3SiS 2Cd 2 with a central four-membered Cd 2S 2 ring. According to the mass spectra the dimeric molecule is not preserved in the vapour phase. The compound is also characterized by 1H, 13C, 29Si NMR and UV spectra. Reactions with 1,10-phenanthroline and 2,2′-bipyridine afforded adducts with formal (RS) 2,Cd(NN) stoichiometry. The central Cd 2S 2 kernel is folded with an angle of 150.6° at the CdCd diagonal. The cadmium atoms are three-fold bonded to thiolate sulphur atoms and the plane coordination is Cd(μ-SR) 2(SR) with the mean distances of d(Cdμ-S) 256.0 pm and d(CdS) 240.8 pm. Additionally, there are weaker interactions with two oxygen atoms of two different tri-tert-butoxysilanethiolate ligands [d(CdO) 268 and 289 pm]. The comparison with the corresponding lead compound clearly shows the influence of the stereochemically active lone electron pair at lead(II).