Potential Surfaces for Unimolecular and Bimolecular Gas Phase Reactions of BHmCln Calculated at the G2 Level of Theory

Abstract

Transition structures and reaction paths for the BHmCln system have been characterized at the MP2(full)/6-31G(d) level of theory; heats of reaction and barriers have been computed at the G2 level of theory. Calculations show that the insertion reactions of BHmCln into H2 and HCl (m + n = 0, 1, 2) occur by highly distorted, non-least motion transition states, with barriers that increase with chlorine substitution on boron. Hydrogen abstraction from BH and BH3-nCln by chlorine proceeds with little or no barrier by a linear transition state. By contrast, BH3-nCln + H → BH2-nCln + H2 occurs by an addition−elimination path via a tetracoordinate intermediate. Likewise, BH2-nCln + X → BH1-nCln + HX or BH2-nCln-1 + XCl (X = H, Cl) are also addition−elimination processes. Abstraction of Cl from BCl and BH3-nCln by H is endothermic and occurs by a bent transition state.