Effect of halogen substituents on C-N bond strength in nitromethane

► We studied effect of halogen substituents on C-N bond strength in nitromethane. ► Multilevel composite and DFT methods were employed. ► Formation enthalpies were calculated using atomization approach and isodesmic reactions. ► It was found that accumulation of chlorine atoms has significantly stronger effect on C-N bond strength. ► Involving of isodesmic reactions improve drastically accuracy of B3LYP estimations.