Synthesis and Molecular Structures in the Gas Phase of <i>N</i>,<i>N</i>-Dimethylaminoxy-trimethylsilane and -trimethylgermane

Abstract

The compounds Me 3 SiONMe 2 and Me 3 GeONMe 2 have been prepared by reacting Me 3 SiCl and Me 3 GeBr with LiONMe 2 . Their identity was proven by gas-phase IR and solution NMR spectroscopy of the nuclei 1 H, 13 C, 15 N, 17 O, 29 Si, and 73 Ge and by mass spectrometry and elemental analyses. Their molecular structures in the gas phase have been determined by analysis of electron diffraction data augmented by restraints derived from ab initio calculations. The molecules adopt C s symmetry. Important geometry parameter values for Me 3 SiONMe 2 are: Si−O 1.688(2), Si−C in - plane 1.870(4), Si−C out-of - plane 1.872(2), O−N 1.481(6) Å, Si−O−N 107.9(6), O−Si−C in - plane 102.1(6), O−Si−C out-of - plane 110.9(7)°, for Me 3 GeONMe 2: Ge−O 1.812(2), Ge−C in - plane 1.949(3), Ge−C out-of - plane 1.950(2), O−N 1.475(6) Å, Ge−O−N 108.9(7), O−Ge−C in - plane 101.7(6), O−Ge−C out-of - plane 110.3(14)°. The structure data are interpreted in terms of weak attractive interactions between the nitrogen donor and the silicon/germanium acceptor atoms. The results are discussed in comparison with other structure data from the literature: the strength of a donor−acceptor interaction in Me 3 SiONMe 2 is weaker than in H 3 SiONMe 2 or ClH 2 SiONMe 2, but stronger than in Me 3 SiON(CF 3 ) 2 .