Synthesis, Fluorescence Properties and Comparison Studies on 2-aminophenol Derivatives: Insights from DFT, Topology, Non-covalent Interactions and Molecular Docking Studies.

Abstract

In this study, Schiff base was synthesized under condensation reaction and thoroughly characterized using ¹H and ¹³C NMR, FT-IR, UV-Vis, and fluorescence spectroscopy. Structural analysis revealed that these compounds predominantly exist in the E-conformation, stabilized by an intramolecular six-membered-ring hydrogen bond. Notably, chloro-functionalized Schiff bases exhibit an additional weak intramolecular C-H···Cl hydrogen bond. Photophysical studies indicate that compounds 2AM24Cl and SA2AM exclusively exhibit long-wavelength emission. Furthermore, the geometric structures, FMOs, and absorption spectrum were elucidated using DFT and TD-DFT calculations. The FMO study calculated energy gaps are 3.54 eV and 3.65 eV for 2AM24CL and SA2AM, respectively. The compounds 2AM24Cl and SA2AM show a good emission (fluorescence) spectrum, it good matched in theoretical fluorescence spectrum. Electron density distribution was visualized through color-mapped representations. Molecular docking studies demonstrated significant interactions between these Schiff base derivatives and amino acid residues, reinforcing their potential biological relevance. The 2AM24CL compound's lowest binding energy is -5.45 kcal/mol and the SA2AM compound's lowest binding energy is -5.66 kcal/mol, with an inhibition constant is 101.54 μm for 2AM24Cl and 71.33 μm for SA2AM, respectively.