Quantum computational, spectroscopic characterization, Hirshfeld analysis & molecular docking studies on p-toluenesulfonic acid (p-TSA) or tosylic acid

Abstract

In this work, characterization by 1H & 13C together with UV-Vis & IR spectroscopy has been accomplished for p-toluenesulfonic acid (p-TSA). The structural, electronic and vibrational properties of the heading compound were foretold using quantum chemical calculations through DFT. All the calculated data were compared with the experimental and found to be consisting with them. The comparison of computed data with experimental have been shown in terms of RMSD values (in case of IR, 1H and 13C NMR). The B3LYP functional with source set 6-311++G(d,p) was utilized to optimize the geometry of the compound, p-TSA. IR spectrum measurements have been made between 4000 - 400 cm−1. To calculate geometric dimensions, energies & wavenumbers, as well as to assign fundamental vibrations, the vibrational modes with the PED assignments were utilized. In solvents namely, MeOH and DMSO, the spectra of UV-Vis of the caption compound were captured between 200 and 400 nm.TD-DFT computations were used to ascertain the HOMO – LUMO energy gap & electronic transitions, which also replicate the UV-Vis absorption spectra. Hirsfeld Surface Analysis (HF) was also evaluated to determine the crystal structure's interactions. The electrophilic and nucleophilic locations were identified using the MEP. Furthermore, to study the biologic functions of p-TSA and to assess the optimum interactions of ligand – protein and similarity to the energetic ingredient, molecular docking was carried out.

Keywords

• FT-IR
• UV-visible
• Molecular docking
• Hirshfeld analysis
• DFT