CONTRIBUTIONS TO THE CHEMISTRY OF SILICON SULFUR-COMPOUNDS .60. SYNTHESIS, MOLECULAR-STRUCTURE AND PROPERTIES OF THE DIMERIC CADMIUM(II) BIS(TRI-TERT-BUTOXYSILANETHIOLATE) ([TERT-C4H9O)3SIS]2CD)2

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-C4H9O)3SiS]2Cd}2 with a central four-membered Cd2S2 ring. According to the mass spectra the dimeric molecule is not preserved in the vapour phase. The compound is also characterized by H-1, C-13, Si-29 NMR and UV spectra. Reactions with 1,10-phenanthroline and 2,2'-bipyridine afforded adducts with formal (RS)2Cd(N-N) stoichiometry. The central Cd2S2 kernel is folded with an angle of 150.6-degrees at the Cd-Cd diagonal. The cadmium atoms are three-fold bonded to thiolate sulphur atoms and the plane coordination is Cd(mu-SR)2(SR) with the mean distances of d(Cd-mu-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).