Toxicity analysis of benzidine through chemical reactivity and selectivity profiles: a DFT approach

Abstract

Chemical reactivity descriptors based on density functional theory are useful in analyzing the toxicities and in identifying the reactive sites of the molecular systems. In the present investigation the global reactivity profiles such as electronegativity, chemical hardness, polarizability, electrophilicity index and local selectivity profiles like condensed electrophilicity of benzidine are calculated using B3LYP/6-31G^* including both Hartree-Fock and density functional theory based exchange functionals (B3LYP) in order to gain deeper insights into the toxic nature of this compound. Both global and local electrophilicity have been found to be adequate in explaining respectively the overall toxicity and the most probable site of reactivity. Interaction between benzidine and nucleic acid (NA) base/selected base pairs and Aryl Hydrocarbon Hydroxylase (AHH) receptors are determined using Parr's formula. The charge transfer involved in the formation of adducts is also qualitatively studied. The results revealed that benzidine acts as an electron-donating agent in their interaction with biomolecules. The planarity and electron affinity are the criteria influencing the toxic nature of benzidine.