SYNTHESIS, PROPERTIES AND CHARACTERIZATION OF OCTADECAMETHYLBICYCLO[4.4.0]DECASILANE

The title compound 1 was obtained by Wurtz-type dehalogenative coupling of sym-dichlorotetramethyldisilane and trichloromethylsilane under appropriate conditions. Spectroscopic data for 1 are compared with those for bi(undecamethylcyclopentasilanyl) (2), a possible structural isomer. An X-ray structural study and Si-29-INEPT-INADEQUATE-NMR spectroscopy confirmed that only the trans-isomer of 1 is formed. Several attempts were made to obtain functional derivatives, but monocyclic and catenated oligosilanes were always obtained owing to breakdown of the bicyclic compound. Chemical and electrolytic reduction towards an anion radical was carried out at various temperatures. The ESR signal at 150 K shows an overlap of two distinct species; along with the spectrum of the well known Si5Me10-. radical anion that of a hitherto unknown species was observed.