Unravelling the thermodynamics and binding interactions of bovine serum albumin (BSA) with thiazole based carbohydrazide: Multi-spectroscopic, DFT and molecular dynamics approach

In the present manuscript, a novel 2-((4-chlorophenyl)amino)-N'-(4-(diethylamino)-2-hydroxybenzylid ene)thiazole-4-carbohydrazide (H1) has been synthesized and characterized using various spectroscopic techniques including 1D, 2D NMR, FT-IR and single-crystal XRD. Various electrostatic parameters such as frontier molecular orbital (FMO), natural bond orbital (NBO), Fukui functions and nonlinear opti-cal (NLO) properties were explored by Density Functional Theory (DFT) using B3LYP/6-311 + G(d,p) level of theory. The effect of solvent polarity on electronic absorption spectra was investigated using Time dependent-DFT. The thermodynamic parameters such as heat capacity, entropy and enthalpy were also investigated at different temperatures. Moreover, photophysical studies were performed to examine the effect of solvent polarity and viscosity. A positive solvatochromism and a 7 fold fluorescence enhance-ment were observed with the increase of solvent polarity and viscosity, respectively. The compound ex-hibit aggregation-induced emission in THF:H2O system. The binding interaction of H1 with BSA and its mechanism has been investigated using UV-visible absorption and fluorescence quenching techniques. The thermodynamics of binding suggest the presence of spontaneous hydrogen bonding interactions, as -ve values of AG, AS and AH were observed. The experimental results obtained from BSA binding stud-ies were validated through in silico molecular docking and dynamics techniques. Molecular modelling studies perfectly corroborate the experimentally obtained results.(c) 2022 Elsevier B.V. All rights reserved.