Here, we synthesized a new coumarinyl chalcone derivative 3-[3-(3-Methyl-thiophen-2-yl)-acryloyl]-chromen-2-one (MTC) by simple and proficient method. A comprehensive study on the photophysics of a coumarinyl chalcone derivative having pi-conjugated potential chromophore system 3-[3-(3-Methyl-thiophen-2-yl)-acryloyl]-chromen-2-one (MTC) has been carried out spectroscopically. The electronic absorption and emission characteristic of MTC were studied in different protic and aprotic solvents using absorption and steady-state fluorescence techniques. The spectral behavior of this compound is found to be extremely sensitive to the polarity and hydrogen bonding nature of the solvent. The compound shows very strong solvent polarity dependent changes in their photophysical characteristics, namely, remarkable red shift in the emission spectra with increasing solvent polarity, change in Stokes shift, significant reduction in the fluorescence quantum yield; indicating that the fluorescence states of these compounds are of intramolecular charge transfer (ICT) character. The solvent effect on the photophysical parameters such as singlet absorption, molar absorptivity, oscillator strength, dipole moment, fluorescence spectra, and fluorescence quantum yield of the compound has been investigated in detail. The difference between the excited and ground state dipole moments (Δμ) were estimated from solvatochromic methods using Lippert-Mataga and Reichardt's correlations. The prepared compound was also studied by density functional theory (DFT) and time-dependent density functional theory (TDDFT). The results revealed that it could be easily reproduce by computational means.
Keywords: Coumarin derivative; Effect of solvent; ICT; Photophysics.