FT-IR, UV spectroscopic and DFT quantum chemical study on the molecular conformation, vibrational and electronic transitions of 2-aminoterephthalic acid

In this work, the molecular conformation, vibrational and electronic analysis of 2-aminoterephthalic acid are presented for the ground state using FT-IR experimental technique and density functional theory (DFT) employing B3LYP exchange correlation functional with the 6-311++G(d,p) basis set. FT-IR spectrum was recorded in the region of 400–4000 cm−1. The ultraviolet absorption spectrum of studied compound that dissolved in ethanol was examined in the range of 190–450 nm. The complete assignments of fundamental vibrations were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Optimized structure of title compound was interpreted and compared with the earlier reported experimental values of a similar compound. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach.