Experimental and theoretical study on solvent and substituent effects on the intramolecular charge transfer in 3-[(4-substituted)phenylamino]isobenzofuran-1(3H)-ones

Abstract

The substituent and solvent effects on solvatochromism in 3-[(4-substituted) phenylamino]isobenzofuran-1(3H)-ones were studied using experimental and theoretical methodologies. The effect of specific and non-specific solvent–solute interactions on the shifts of UV–Vis absorption maxima were evaluated using the Kamlet–Taft and Catalán solvent parameter sets. The experimental results were studied by density functional theory (DT) and time-dependent density functional theory (TD-DFT). The HOMO/LUMO energies (EHOMO/ELUMO) and energy gap (Egap) values, as well as the mechanism of electronic excitations and the changes in the electron density distribution in both ground and excited states of the investigated molecules were studied by calculation in the gas phase. The electronic excitations were calculated by the TD-DFT method in the solvent methanol. It was found that both substituents and solvents influence the degree of π-electron conjugation of the synthesized molecules and affect the intramolecular charge transfer character. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172013]

Keywords

• phthalides
• solvatochromism
• substituent effect
• LSER
• quantum chemical calculation