Theoretical insight into the structure and bonding characteristics of Bisphenol-A. QTAIM and NBO analyses

Abstract

Bisphenol-A (BPA) is considered as one of the most suspicious disruptors. Exposure to BPA may bring about possible human toxicities. BPA is an emerging contaminant widely used in manufacturing of epoxy, unsaturated polyester-styreneand polycarbonate resins. BPA is released into the environment through industrial and municipal wastewater discharges; its degradation products are probably more dangerous than BPA itself. The present study aims at a better insight into its ground state electronic and acid–base properties, and the mechanism of its thermal decomposition. Density functional theory (DFT) is utilized to study the geometry, electronic structure and electrostatic potential (ESP) for BPA. The molecule is noncoplanar with one of the phenolate moieties forced out of the plane by 57[Formula: see text]. This might very well determine the dissociation reaction pathway and in the meantime facilitates strong conjugation and considerable delocalization along the rest of the molecule. Proton affinities and deprotonation enthalpies are computed and discussed. Bonding characteristics are investigated within the natural bond-orbital (NBO) and quantum theory of atom in molecule (QTAIM) frameworks.