Matrix IR spectroscopic study of the vacuum pyrolysis of octamethylcyclotetrasiloxane, allyloxy- and allyl(allyloxy)dimethylsilanes as well as 2,2,6-trimethyl-2-silapyrane as potential sources of dimethylsilanone

Article abstract of DOI:10.1016/0022-328X(89)87139-6

The mechanism of vacuum pyrolysis of octamethylcyclotetrasiloxane, allyloxy- and allyl(allyloxy)-dimethylsilanes, and 2,2,6-trimethyl-2-silapyrane, potential sources of transient dimethylsilanone, has been studied by matrix isolation IR spectroscopy.Only in the case of allyloxydimethylsilane is there direct evidence of silanone (CH3)2Si=O formation, by observation of its most intense band at 798 cm^-1 in the matrix IR spectrum of pyrolysis products.In all other cases the intermediate, (CH3)2Si=O, was found to be thermally unstable, undergoing fragmentation into SiO molecules and CH3 radicals, thus indicating silanone participation in the reactions studied.