Comparative Computational Studies of Gaseous Alkali Metal Amidoboranes MNH2BH3 and their Carbon Analogs MC2H5 (M = Li - Cs): Formation and Unimolecular Hydrogen Evolution

Abstract

Comparative computational studies of reaction mechanisms of formation and unimolecular hydrogen evolution from alkali metal amidoboranes MNH2BH3 and their carbon analogs MC2H5 (M = Li - Cs) were performed at the B3LYP/def2-TZVPPD level of theory. Transition states (TS) for the consecutive dehydrogenation reactions were optimized. In contrast to endergonic dehydrogenation of carbon analogs, dehydrogenation reactions of alkali metal amidoboranes are exergonic at room temperature. The nature of the alkali metal does not significantly affect the thermodynamic characteristics and activation energies of unimolecular gas phase dehydrogenation reactions. The influence of the alkali metal is qualitatively similar for amidoboranes and their carbon analogs.