PUB - Publikationen an der Universität Bielefeld

O-(Dichlorosilyl)-N,N-dimethylhydroxylamine, Cl2HSiONMe2, was synthesised by the reaction of O-lithio-NN-dimethylhydroxylamine with an excess of trichlorosilane. The compound was characterised by multinuclear NMR spectroscopy (H-1, C-13, N-15, Si-29), gas-phase IR spectroscopy and mass spectrometry. The structure of Cl2HSiONMe2 was determined by gas-phase electron diffraction. It exists as two conformers in the vapour, named anti and gauche after the position of the SiH hydrogen atom relative to the SiON skeleton. The anti:gauche ratio in the vapour was determined to be 40:60. The anti conformer shows only a weak attractive interaction between the geminal donor and acceptor centres N and Si [angle Si-O-N 111.1(20)degrees], whereas these interactions are stronger in the gauche conformer [angle Si-O-N 98.8(12)degrees]. Further structure-determining forces from weak hydrogen bridges of the Si-(ClH)-H-...-C type and van der Waals repulsive forces are also discussed. The experimental results are in reasonable agreement with ab initio calculations at the MP2/6-311++G** level of theory.