Investigation of Structural, Vibrational Properties and Electronic Structure of Fluorene‐9‐Bisphenol: A DFT Approach

Bisphenol A (BPA) is a chemical used in a variety of materials and has adverse effects on endocrine system. The substitutes of BPA have been developed to produce BPA‐free plastics. Fluorene‐9‐bisphenol (BPFL), has anti‐oestrogenic effects, is one of those substitutes used in ‘BPA‐free’ bottles. In this study, the physical, electronic and vibrational properties of BPFL molecule are investigated using density functional theory (DFT) calculations at B3LYP/6‐311G (d, p) basis set. Bond distances, Fourier transform infrared (FT‐IR) spectra, natural atomic charges, solvation energies, dipole moments and vibrational frequencies were carried out. The calculated bond distance for the optimized geometry of BPFL obtained from DFT calculations were compared with the measured results. Structural properties like radial distribution function (RDF) and probability distribution depending on coordination number have been calculated for the molecule. Ultraviolet–visible (UV‐Vis) spectra characteristics and the electronic features, such as absorption wavelengths, frontier orbitals, excitation energies and band gap energy of BPFL were also recorded using time‐dependent (TD) DFT approach based on optimized structure with different solvent environments. Finally, we investigated the effects of solvents on structural, electronic and vibrational frequencies of BPFL molecule. The density of states (DOS or TDOS) is the number of different states at a particular energy level. DOS is important, because the occupied and unoccupied molecular orbitals can be seen on DOS spectrum. Using Mulliken population analysis, we have plotted total density of state (TDOS) spectrum (see Figure). Figure indicate that the molecular orbitals and energy gap ΔE between frontier HOMO and LUMO of BPFL molecule. Green and red colours represent the positive and negative isosurfaces for HUMO and LUMO, respectively.