MULTIPLY-BONDED SILICON - MATRIX-ISOLATION AND CHEMICAL TRAPPING OF PRODUCTS OF PYROLYSIS AND PHOTOLYSIS OF TRIAZIDOPHENYLSILANE

Triazidophenylsilane (1) yields phenyl isosilacyanide (3) upon irradia tion in matrix isolation and by pyrolysis followed by trapping in nobl e gas matrix. Annealing from 12 to 15 K causes significant changes in the IR spectrum of photochemically produced 3, attributed to the relea se of hydrostatic pressure in the matrix. The matrix reaction of pyrol ytically produced 3 with t-BuOH to yield an independently synthesized trapping adduct 4 has been followed spectrally. An aligned sample of 3 was produced by photoselection and polarized IR spectra were recorded . The UV and IR absorption spectra of 3 have been interpreted and agre e well with ab initio and semiempirical calculations. In contrast, the intermediacy of benzenesilonitrile (2), a representative of a so far unknown class of species with a -Si=N triple bond, in the photofragmen tation of matrix-isolated 1, is merely strongly suggested but not prov en by trapping of the photoproducts from matrix-isolated 1 with t-BuOH to yield the adduct 5 in addition to 4. The silonitrile 2 did not acc umulate in the matrix in amounts sufficient for spectral characterizat ion.