Ab initio study of the mechanism of forming a spiro-Si-heterocyclic ring compound involving Ge from H2Ge=Si: and acetaldehyde

Abstract

The H2Ge=Si: and its derivatives(X2Ge=Si:, X = H, Me, F, Cl, Br, Ph, Ar……) is a new species. Its cycloaddition reactions is a new area for the study of silylene chemistry. The mechanism of the cycloaddition reaction between singlet H2Ge=Si: and acetaldehyde has been investigated with MP2/6-311++G** method, From the potential energy profile, it can be predicted that the reaction has a dominant reaction pathway. The reaction rule presented is that the two reactants firstly form a four-membered Ge-heterocyclic ring silylene through the [2+2] cycloaddition reaction. Because of the 3p unoccupied orbital of Si: atom in the four-membered Ge-heterocyclic ring silylene and the π orbital of acetaldehyde form a π→p donor-acceptor bond, the four-membered Ge-heterocyclic ring silylene further combines with acetaldehyde to form an intermediate. Then the intermediate isomerizes to a spiro-Si-heterocyclic ring compound involving Ge via a transition state.

Keywords

• H2Ge=Si:
• four-membered Ge-heterocyclic ring silylene
• spiro-Si-heterocyclic ring compound
• potential energy profile