THE PHOTOLYSIS OF 1,1-DIMETHYLSILACYCLOBUTANE IN THE GAS PHASE

Article abstract of DOI:10.1016/S0022-328X(00)87921-8

The gas phase photolysis of 1,1-dimethylsilacyclobutane (DMSCB) has been carried out at wavelengths 185 nm < λ < 210 nm.The major products of the photodissociation are ethylene and 1,1,3,3-tetramethyl-1,3-disilacyclobutane (TMDSCB).The relative quantum yield Φ(C2H4)/Φ(TMDSCB) = 8.0 +/- 0.5 in neat DMSCB is independent of the initial pressure but decreases to a limiting value of ca. 4.5 in the presence of H2.The silicon mass deficit is accounted for, qualitatively, by the production of an involatile polymeric material, of approximate composition -(Me2SiCH2)x-, onphotolysis.Under these conditions, Me2-Si=CH2 undergoes an oligomerisation reaction in addition to the established homogeneous dimerisation reaction to form TMDSCB.