Spectroscopic (FT-IR, FT-Raman, UV–Vis and NMR) and computational (DFT, MESP, NBO, NCI, LOL, ELF, RDG and QTAIM) profiling of 5‑chloro-2‑hydroxy-3-methoxybenzaldehyde: A promising antitumor agent

Abstract

In this study, the benzaldehyde derivative 5-chloro-2-hydroxy-3-methoxybenzaldehyde (5C2H3MB) was characterized using spectroscopic techniques. Geometric parameters and complete fundamental vibrational assignments were simulated using DFT/B3LYP/6-311++G(d,p). The 1H and 13C chemical shifts, computed using the GIAO method, were in agreement with the experimental findings. The electronic properties of 5C2H3MB were analyzed using time-dependent density functional theory (TD-DFT) to determine various electronic parameters, including HOMO-LUMO energies. NBO analysis was performed to determine the numerous hyper-conjugative interactions responsible for the stability of the compound. In addition, Mulliken population analysis and Molecular Electrostatic Potential Surfaces (MESP) analysis were conducted to identify electron-rich, electron-poor, reactive sites, and bonding characteristics of the titled compound. The topological analyses ELF, LOL, NCI, QTAIM, and RDG were performed using Multiwfn software, and global reactivity parameters and Fukui functions were also predicted. Molecular docking studies were conducted to confirm the biological activity by simulating the binding orientation and affinity of 5C2H3MB against transferase inhibitor and human phosphorylated IRE1 alpha, showing a binding energy of −5.1, −5.3 and −5.9 kcal/mol, indicating its potential as an antagonist.