Dative stabilization of carbocations

Carbocations are well known intermediates in organic chemistry. While many carbocations are not stable enough to exist themselves, they may be stabilized by several factors, including resonance with nearby electron donors. Reactions that proceed via mechanisms involving carbocations include the Baeyer-Villiger reaction and the Criegee rearrangement. In both cases, the carbocation is stabilized through resonance by an oxygen atom. The role that oxygen plays in stabilizing carbocations was studied theoretically. The structures of several carbocations, based on the t-butyl ion, with varying numbers of oxygen atoms were optimized using second order Møller-Plesset perturbation theory methods. Relationships were found between the number of oxygen atoms and the amount of delocalization, as well as the charge of the formally positive carbon atom and the number of oxygen atoms bonded to it. Another study was performed on a set of larger cations. Evidence was found relating to the presence of dative bonds, the strength of which were found to be dependent on a number of factors.