Mechanism of H/D exchange in the reaction of BH2+ + deuterium

Ionization of diborane by electron impact in the source of a Flowing Afterglow-Selected Ion Flow Tube (FA-SIFT) gives rise to an enormous number of borohydride anions and cations. Many of these ions have been identified by earlier studies in an ICR, or analyzed using ab initio computations. Because boron consists of appreciable amounts of two isotopes, 10B and 11B, several different ionic species may appear at the same mass. The ion at m/z=13 is purely the 11BH2+ isotopomer. The FA-SIFT enables selection of this ion out of the source mixture using a source quadrupole. This open-quotes SIFTedclose quotes ion can then be injected into a second flow tube for reaction studies. The chemistry of BH2+ has been initially probed by studying the mechanism and energetics of H/D exchange in the reaction of BH2+ + D2. BH2+ is the boron analog of methyl cation, and it is hoped that comparisons of the chemistry of these two ions will elucidate mechanistic aspects of the reactions of methyl cation. Ab initio computations have been carried out to help define the reaction pathway