Ab initio study of mechanism of forming bis-heterocyclic compound with Si and Ge between silylene germylene (H2Si=Ge:) and formaldehyde

Abstract

The mechanism of the cycloaddition reaction between singlet state silylene germylene (H2Si=Ge:) and formaldehyde has been investigated with the CCSD(T)//MP2/cc-pvtz method, from the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rules presented is that [2 + 2] cycloaddition reaction between two reactants firstly generates a Si-heterocyclic four-membered ring germylene. Because of the 4p unoccupied orbital of the Ge atom in (the) Si-heterocyclic four-membered ring germylene and the π orbital of formaldehyde forming a π → p donor–acceptor bond, the Si-heterocyclic four-membered ring germylene further combines with formaldehyde to form an intermediate. Because the Ge atom in intermediate happens sp 3 hybridization after transition state, then, intermediate isomerizes to a bis-heterocyclic compound with Si and Ge via a transition state.