29Si-NMR-spektroskopische untersuchungen an substituierten disilanen

The ²⁹Si chemical shifts δ(Si) and coupling constants J(SiSi) and J(SiC) for a series of substituted tetra- and penta-methyldisilanes are reported and discussed as well as the corresponding data of di- and poly-silanes from the literature. The substituent effects of /gd(Si) can be explained satisfactorily by a simple quantum-chemical model without consideration of d-orbital effects and are mainly affected by the distribution of the /gs-electron density at the Si atom under study. The influence of steric interactions on δ(Si) is investigated in the case of alkoxy-substituted disilanes. A short discussion of the substituent effects on the coupling constants J(SiSi) and J(SiC) is given.