HETERO-PI-SYSTEMS - 24 - SILYLENES OF THE ELEMENTAL COMPOSITION C4H2SI - GENERATION AND MATRIX-SPECTROSCOPIC IDENTIFICATION

Flash pyrolysis of 1,1-diethynyl-2,2,2-trimethyldisilane (16) and trie thynylsilane (18) led to the formation of two silylenes of the element al composition C4H2Si, namely diethynylsilylene (10) and ethynylsilacy clopropenylidene (7), which were isolated in an argon matrix at 10 K. Both compounds could be photoconverted into another isomer, butadiynyl silylene (9). The identification of these reactive intermediates is ba sed on the comparison between the experimental and calculated IR spect ra for the parent compounds as well as for their dideuterated and full y C-13-labeled isotopomers.