Some dimethyl ether adducts of silyl and germyl halides

Abstract

The 1 : 1 adducts of dimethyl ether with silyl chloride, silyl bromide, and germyl chloride, which are stable only below their melting points, are reported. A single-crystal X-ray diffraction study of the silyl chloride adduct at 100 K shows that it contains simple, non-interacting adduct molecules, and the X-ray powder pattern of the silyl bromide adduct at 113 K shows it to be isostructural with the chloride adduct. The Raman and i.r. spectra of the solid adducts are described; they suggest that all three have similar structures. Assignments are suggested for the bands observed, including the M–O stretch. This appears at a very low frequency, which is consistent with the Si–O ‘bond’ in the silyl chloride adduct [227.24(12) pm] being much longer than normal Si–O single bonds. The bonding between the ether oxygen and silicon or germanium is discussed in terms of the involvement of valence-shell d and possibly M–X antibonding orbitals as acceptors.