Effects of temperature and solvent polarity on the thermodynamic and photophysical properties of ferulic acid using density functional theory (DFT)

Abstract

Ferulic acid (FA) possesses diverse biological properties and is extensively utilized in pharmaceuticals, cosmetics, and the food industry due to its non-toxic nature. However, environmental factors such as temperature and solvent polarity play a significant role in influencing the thermodynamic and photophysical properties of drugs, particularly during the drug optimization and design phases. This study investigates the impact of temperature and solvent polarity on the thermodynamic and optical properties of FA using density functional theory (DFT) with the B3LYP functional approach and the 6-311++G(d, p) basis set under various solvent and gas conditions. Additionally, vertical UV-vis absorption and emission spectra of FA in different solvent polarities and gas phases were analyzed using time-dependent density-functional theory (TDDFT) with the B3LYP method and the 6-31++G(d, p) basis set. Applying Koopman's theory, the chemical activity of FA was assessed based on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) values. The findings indicate that an increase in temperature within the range of 100–1000 K leads to elevated enthalpy, heat capacity, and entropy due to molecular vibrational activity, resulting in FA degradation and instability. Furthermore, thermodynamic parameters, HOMO and LUMO values, and the chemical activity of FA were also influenced by different solvent polarities. The absorption and emission spectra of FA exhibited a red shift due to interactions with solvents and solutes. Overall, this study analyzed the significance of environmental factors such as temperature and solvent polarity in pharmaceutical design and optimization processes to enhance drug efficacy and stability.