The Reaction of Dimethylsilylene with Carbon Tetrachloride in Solution Studied by Means of Spin Chemistry and Laser Pulse Photolysis Methods

The interaction between dimethylsilylene (Me 2 Si, DMS) generated through the photolysis of 7,7'-dimethyl-1,4,5,6-tetraphenyl-2,3-benzo-7-silanorbornadiene (I) and carbon tetrachloride has been studied by means of laser pulse photolysis and spin chemistry methods. The reactions of dimethylsilylene in excited triplet and ground singlet states have been described. From the analysis of magnetic effect, the interaction of triplet dimethylsilylene with carbon tetrachloride has been demonstrated. The laser pulse photolysis experiments have shown that the reaction of singlet dimethylsilylene with CCl 4 proceeds via the intermediate formation of a donor-acceptor complex (Me 2 Si/ClCCl 3 , λ m a x = 334 nm). Its decay is supposed to occur via the reaction with I (k = 1.26 x 10 7 M - 1 .s - 1 ) and via the disproportionation process (2k b i m /∈ = 1.07 x 10 6 cm.s - 1 ). The lifetimes of different spin states of DMS have been estimated in the frames of the proposed kinetic scheme (τ S ≤ 3.2 x 10 - 7 s, τ T ≤ 1.4 x 10 - 7 s).