DFT calculations of 2,4,6-trinitrophenylbenzoate derivatives: Structure, ground state properties and spectral properties

Abstract

Abstract 2,4,6-Trinitrophenylbenzoate derivatives 3 ( a – g ) were synthesised and their optimum molecular geometries, ground state properties, IR, UV and NMR spectra were calculated using the B3LYP method with 6-31G ** Pople basis set. The predicted geometry showed that the aryl-oxygen bond is stronger than acyl-oxygen bond. Bond lengths are affected by the presence of electron donating or electron withdrawing groups in benzoyl moiety. The orientation of the two aryl rings with respect to each other is neither in the same plane nor perpendicular. Hammett plot showed good linearity between substituent constant and the HOMO as well as LUMO energies. Mulliken and NBO charges indicate that the carbonyl carbon (C7) is more positively charged than the ipso carbon (C10), while the inspection of the coefficient on the carbonyl carbon and the ipso carbon atom for LUMO showed that its value is greater for C10 compared to C7. The correlation between the experimental and the theoretical results indicates that density functional theory B3LYP method is able to provide satisfactory results for predicting IR, UV and NMR properties.