Noble gas catalysed 1,2-migrations in N2H+ and N2CH3+

Abstract

Molecular orbital calculations are reported for N2H+ and N2CH3+ and for the transition structures for the rearrangement of these ions by 1,2-shifts of H and CH3. All reaction profiles were also calculated with one atom of noble gas, M, present (M = Ne, Ar, Kr). Structure optimizations were performed at B3LYP/6-311++G(d,p) and, in the case of N2H+···M, single point calculations were also performed at QCISD(T)(full)/6-311++G(2df,p). For N2H+, inclusion of one noble gas atom reduces the barrier to rearrangement from 46.6 kcal mol-1 for the uncatalysed reaction to 42.6 kcal mol-1 (by Ne), to 21.4 kcal mol-1 (by Ar), and to 11.0 kcal mol-1 (by Kr). For N2CH3+, the barrier of 36.4 kcal mol-1 is reduced to 35.1 kcal mol-1 by Ne, to 27.4 kcal mol-1 by Ar, and to 18.4 kcal mol-1 by Kr.Key words: catalysis, molecular orbital theory, argon, krypton.