Theoretical study on the bridging ability of oxygen and sulphur in vinyl cations

Abstract

A non-empirical SCF-MO investigation with split-valence basis sets was performed on C₂H₂OH⁺ and C₂H₂SH⁺ cations. The four limiting structures corresponding to pyramidal and planar bridged ions and to s-cis- and s-trans-vinyl cations were fully optimized and interconnected through an energy surface. In both cases the planar bridged structure is on an energy maximum, whereas the other three structures correspond to stable conformations. The geometrical and electronic properties of the limiting structures are discussed as well as the interconversion processes among them.