摘要 : The structure, thermochemistry, isomerization and dissociation of the CH2BH2, and CH3BH radicals, cations and anions have been explored with a wide range of ab initio levels of computational theory and their formation has been pro... 展开 The structure, thermochemistry, isomerization and dissociation of the CH2BH2, and CH3BH radicals, cations and anions have been explored with a wide range of ab initio levels of computational theory and their formation has been probed by tandem mass spectrometry and RRKM kinetic theory. Calculations predict that CH2BH2]+ is not an equilibrium structure on the potential energy surface. The CH3BH]+ was characterized by its collision-induced dissociation mass spectrum and neutralization-reionization (NR) mass spectrometry was used to generate the CH3BH]center dot radical. While both CH2BH2]center dot. and CH3BH]center dot are stable with respect to isomerization and dissociation, a relatively low barrier to the 1,2-hydrogen shift means that pure CH3BH]center dot can only be made cold, and so the above NR experiment likely produces a mixture of neutrals, of which only CH3BH]center dot can be reionized. Vertical electron attachment to CH3BH]center dot is endothermic which means the CH3BH]- anion is unlikely to be made from the cation or radical. In addition, the anion lies in a shallow well of only 48 kJ mol(-1) and will undergo fast isomerization to CH2BH2]- - below the dissociation limit. (c) 2007 Elsevier B.V. All rights reserved. 收起