Exploring the bond topological properties and the charge depletion-impact sensitivity relationship of high energetic TNT molecule via theoretical charge density analysis

Abstract

To understand the energetic properties of 2,3,4-Trinitrotolune (TNT) molecule, a quantum chemical calculation and the electronic charge density analysis have been performed. The density functional theory (B3P86/6-311G∗∗) calculation was carried out using Gaussian03 software. The energy-minimized wave function obtained from DFT was used for the charge density analysis. The inductive and steric effects of methyl and nitro substituents are not showing any unique geometric and bond topological features on C–C bonds of phenyl ring. A large charge accumulation (∼3.49 eÅ⁻³) is found in NO bonds; its corresponding Laplacian of electron density is ∼−27.6 eÅ⁻⁵, this indicates that the charges of the bonds are highly concentrated. Comparatively, the Laplacian of electron density of C–NO₂ (∼−17.1 eÅ⁻⁵) and C–CH₃ (−14.7 eÅ⁻⁵) bonds are found very less, confirm that the bond charges are significantly depleted; hence these bonds are considered as the weak bonds in the molecule. The isosurface of electrostatic potential of the molecule displays high electronegative region around the nitro groups, which are the reaction surface of the molecule. Present study predicts the relationship between the bond charge depletion and the bond sensitivity. Further, it proposes that, if the highly charge depleted bonds exhibit positive V_mid values, which are the sensitive bonds. We found, C–N bonds are the sensitive bonds in the molecule.