Comparative Trapping Kinetics of SILYLENE. 1. Silylene Reactions with 1,3-Butadiend and Acetylene and with and with 1,3-butadiene and Menthanol

摘要

Relative rate studies of silylene trapping by butadiene, methanol, and acetylene are reported. For the reactions :SiH2 + H2C=CHC(H)=CH2 yields CH2C(H)=CHCH2SiH2 vs. :SiH2 + CH2OH yields CH3OSiH3, 1n (k sub 3/k sub 7) = (5.91 + or - 0.91)-(5846 + or - 1540) cal/RT (696-1016 K), and reaction 3 vs. :SiH2 + HC triple bond CH yields HC=CSiH3, 1n (k sub 3/k sub 6) = (1.51 + or - 0.32)-(712 + or - 520) cal/RT (603-102 K). Relative rates, extrapolated to room temperature, are favorably compared to existing absolute rate constant measurements. On the basis of estimated Arrhenius parameters for the reaction 7, tentative absolute Arrhenius parameters with temperature dependencies for a number of silylene-substrate reactions are calculated. Keywords: Methoxysilane; ethynylsilane; silacyclopentene.