Formation of silylenes in the thermolysis of pentamethyldisilane and 1,1,2-trimethyldisilane

Abstract

Evidence is presented that the title compounds decompose thermally to give silylenes Me₃SiSiMe₂H → Me₂Si + Me₃SiH, log₁₀k/s^–1=(12.93 ± 0.31)–(198.1 ± 3.9) kJ mol^–1/2.303 RT, HMe₂SiSiMeH₂→ Me₂Si + MeSiH₃, log₁₀k/s^–1=(12.56 ± 1.8)–(192.6 ± 22) kJ mol^–1/2.303 RT, HMe₂SiSiMeH₂→ MeSiH + Me₂SiH, log₁₀k/s^–1=(13.66 ± 0.55)–(193.1 ± 5.9) kJ mol^–1/2.303 RT. The significance of these Arrhenius parameters is discussed and ΔH^°_f(Me₂Si)_g is estimated to be 66 ± 10 kJ mol^–1. Some qualitative information on the insertion reactions of Me₂Si and MeSiH is reported.