Kinetics of Silylene Insertion into N−H Bonds and the Mechanism and Kinetics of the Pyrolysis of Dimethylsilylamine

Abstract

Product and kinetic data on the copyrolysis of silane with ammonia and of silane with dimethylamine are reported. The main products of the SiH4/NH3 reaction are disilane and silylamine, and the main products of the SiH4/Me2NH reaction are Si2H6 and Me2NSiH3. The silylamine products are produced by SiH2 insertions into the N−H bonds of the amine reactants, and rate constants for this insertion lie in the k2 ∼ 2 × 109 M-1 s-1 range, with no temperature dependence within the errors. Kinetic and product data on the pyrolysis of dimethysilylamine are also presented. Reactant loss followed reasonable first-order kinetics and produced rate constants consistent with Arrhenius parameters of log A(sec-1) = 12.64 ± 0.98 and E = 48.02 ± 3.1 kcal/mol. A mechanism of reaction, based on the kinds of silylene intermediate reactions expected, is presented. Comparisons of mechanistic expectations with the product data, however, indicate a more complex reaction system.