Complete basis set, Gaussian, and density functional theory study of the vinylidine–acetylene rearrangement

Abstract

A high level of ab initio and density functional theory computational study was performed to determine the reliability of density functional methods and the possibility to experimentally detect vinylidine in the mixture with acetylene. It was determined that vinylidine is 44.9 kcal/mol less stable than acetylene, with an enthalpy of formation of 101.2 kcal/mol and an activation barrier for its rearrangement into acetylene of only 0.4 kcal/mol. Therefore, it was suggested that this acetylene isomer would be difficult to observe experimentally.