Theoretical and experimental studies on electronic structure and photophysical properties of biological active substituted hydroxyquinolin-2(1H)-one fluorophore

Abstract

In this study, the solvents effects on the photophysical characteristics of compound 1-(((4-bromophenyl)amino)(4-methoxyphenyl)methyl)-6-hydroxyquinolin-2(1H)-one (4BMHQ) was investigated using several polarity functions such as Kamlet's and Catalan's methods. The absorption spectral peak was unaffected by changing the solvent polarity; however, under the same circumstances, we observed a red shift of 16 nm in the fluorescence spectral peak as the solvent polarity increased. The system has general hydrogen bonding interactions as well as interactions between solute and solvent. Nonetheless, hydrogen bonding interactions have a lower impact than classical solute-solvent interactions. The ground state dipole moment was calculated using the quantum chemistry approach, while the excited state dipole moments were obtained using solvatochromic data. It is revealed that the excited state dipole moment is greater than the ground state dipole moment. DFT investigations provide the most stable structure and molecular characteristics of a molecule in its ground electronic state. Molecular parameters such as HOMO-LUMO energy, global descriptors, and the potential energy surface were used to investigate the compound's structural features.

Keywords

• Quinoline
• DFT calculations
• Solvatochromic shift
• Dipole moment
• Intramolecular charge transfer