The gas-phase reaction of SiH2 with dimethylether: kinetic evidence for direct formation of a donor-acceptor adduct

Abstract

The kinetics of the title reaction have been investigated at 296 K (3-400 Torr in Ar and 3-50 Torr in SF6), and between 298 and 434 K (5 Torr in Ar). The second-order rate constants increase by ca.×20 between 3 and 400 Torr (Ar) and ca.×6 between 3 and 50 Torr (SF6). At 5 Torr Ar, an Arrhenius plot gives log(A/cm3molecule-1s-1)=-13.71±0.13 and Ea=-15.3±0.9kJmol-1. The data are consistent with the formation of an H2Si...OMe2 donor-acceptor adduct. RRKM/master equation modelling of the rate constants at 296 K gives a high pressure limiting value (k∞) of 6.6×10-10cm3molecule-1s-1 and a binding energy of 96kJmol-1 for the adduct. © 2001 Elsevier Science B.V.