Investigation of molecular structure, vibrational, electronic, NMR and NBO analysis of 5-chloro-1-methyl-4-nitro-1H-imidazole (CMNI) using ab initio HF and DFT calculations

► The properties of nitroimidazoles are of interest due to their pharmaceutical importance. ► The structure, vibrational, electronic and NLO activity of 5-chloro-1-methyl-4-nitro-1H-imidazole (CMNI) was studied. ► The low frontier orbital energy gap explains the eventual charge transfer interaction taking place within the CMNI. ► CMNI exhibited good NLO activity.