Steric effects on the dialkyl substituted X2C2Si silylenes: A theoretical study

Theoretical study on the reaction between silacyclopropenylidene and three-membered heterocyclic compounds (azirane and oxirane): An alternative approach to the formation of heterocyclic silylene

The reaction mechanism between silacyclopropenylidene and three-membered heterocyclic compounds (azirane and oxirane) has been systematically investigated at the B3LYP/6-311+G* level of theory in order to better understand the reactivity of unsaturated cyclic silylene. Geometry optimizations and vibrational analyses have been conducted for the stationary points on the potential energy surface of the system. Calculations show that the Si-spiroheterocyclic intermediate and four-membered heterocyclic silylene compound could be produced through the insertion process and subsequent dissociation process between silacyclopropenylidene and three-membered heterocyclic compounds. For the insertion process, it is easier for silacyclopropenylidene to insert into C-N bond of azirane than into C-O bond of oxirane. This study is helpful to understand the reactivity of silacyclopropenylidene, the evolution of silicon-bearing molecules in space, and to offer an alternative approach to the formation of enlarged heterocyclic silylene compound.