PUB - Publikationen an der Universität Bielefeld

The reaction of dimethylaminosulfenylchloride Me2NSCl with trichlorosilane HSiCl3 and triethylamine gives elemental sulphur and Me2NSiCl3. The aminosulfenylsilane Me2NSSiCl3 is postulated to be an intermediate of this reaction. Ab initio calculations (MP2/6-311G(d,p)) on Me2N-S-SiH3, Me2N-S-SiH2Cl, Me2N-S-SiH2F, and Me2N-S-SiCl3 have been carried out, demonstrating the occurrence of acute valence angles at sulphur and short (SiN)-N-... distances, which are indicative of NSSi three-membered rings. The strength of the (SiN)-N-... interactions depends on the electronegativity of the substituent at silicon in anti-position to the nitrogen atom and is strongest in the anti conformer of Me2N-S-SiH2F (< NSSi 68degrees, (SiN)-N-... 2.208 Angstrom). The coordination spheres of the nitrogen atoms in the Me2N-S-SiR3 molecules are steeply pyramidal, which is in contrast to the planarised N atoms in other SNMe2 compounds, such as Me2NSCl. The crystal structure of this compound has been determined, as well as that of the product of the above reaction, Me2NSiCl3. Both have planar coordination geometries at the nitrogen atoms.