Synthese und spektroskopische Charakterisierung mehrfach silylierter Ethene / Synthesis and Spectroscopic Characterization of Di- and Trisilylethenes

Abstract

Abstract Di- and trisilylethenes have been prepared by catalytic hydrosilylation of trimethylsilyl-, bis-(trimethylsilyl)- and bis(trichlorosilyl)ethyne and converted into the hydrogenated derivatives by LiAlH 4 -reduction. The stereochemistry of the products and the effects of substitution of methyl vs. chlorine ligands on the NMR coupling constants J( 29 Si/ 1 H) have been investigated by analysis of selectively (Me)-decoupled 29 Si NMR spectra. From the results it has been concluded, that the catalytic hydrosilylation of silylated ethynes proceeds in a stereospecific syn fashion yielding trans adducts. Substitution of methyl by chlorine at one or two Si-atoms in tris(trimethylsilyl)ethene leads to an increase of the coupling constant J( 29 Si/ 1 H vinyl) with the chlorinated Si-atoms and reduces the values for those Si-atoms, where the methyl groups are retained.