Formation enthalpies and bond dissociation enthalpies for C1-C4 mononitroalkanes by composite and DFT/B3LYP methods

The gas phase enthalpies of formation of C1-C4 mononitroalkanes were calculated using different multilevel (G1, G2, G3, G3B3, CBS-QB3) and density functional theory (DFT)-based B3LYP techniques. The enthalpies of the C-N bond dissociation of these nitroalkanes were also calculated. The calculated values of the formation and reaction enthalpies were compared with available experimental data. It was found that the G3 and G3B3 procedures gave accurate results for the formation enthalpy of nitroalkanes and radical products. The agreement of the CBS-QB3 calculations with experiment is also satisfactory, whereas less accurate than G3 and G3B3 estimations. The G3 and G3B3 multilevel techniques showed good results for the reaction enthalpies of the C-N bond dissociation.