Effect of molecular structure of nitroalkanes on the C-NO2 bond strength and activation energy of the gas-phase radical decomposition according to the quantum-chemical simulation

Abstract

The non-empirical (MP2 and CCSD), composite (G4), and DFT (B3LYP, CAM-B3LYP, B98, and wB97XD) methods with different basis sets have been employed to compute the formation enthalpies of a series of C1–C4 nitroalkanes and the hydrocarbon radicals formed via the C-N bond rupture as well as the C–N bond dissociation energies. For the series of isomeric nitroalkanes, the effects of the nature of the participating carbon atom (primary, secondary, or tertiary) and the size of adjacent alkyl group on the C-N bond strength have been analyzed. The reasons for different thermochemical and kinetic estimates of the C-N bond dissociation energy in nitroalkanes have been discussed.