Theoretical studies on absorption, emission, and resonance Raman spectra of Coumarin 343 isomers

Abstract

The vibrationally resolved spectral method and quantum chemical calculations are employed to reveal the structural and spectral properties of Coumarin 343 (C343), an ideal candidate for organic dye photosensitizers, in vacuum and solution. The results manifest that the ground-state energies are dominantly determined by different placements of hydrogen atom in carboxylic group of C343 conformations. Compared to those in vacuum, the electronic absorption spectra in methanol solvent show a hyperchromic property together with the redshift and blueshift for the neutral C343 isomers and their deprotonated anions, respectively. From the absorption, emission, and resonance Raman spectra, it is found that the maximal absorption and emission come from low-frequency modes whereas the high-frequency modes have high Raman activities. The detailed spectra are further analyzed for the identification of the conformers and understanding the potential charge transfer mechanism in their photovoltaic applications.

Molecular Design of UV–vis Absorption and Emission Properties in Organic Fluorophores: Toward Larger Bathochromic Shifts, Enhanced Molar Extinction Coefficients, and Greater Stokes Shifts

“…It has been demonstrated that the theoretically optimized molecular structures based on DFT calculations bear good agreement with the experimental derived data using X-ray diffraction. 47,48 TD-DFT has also been shown to be a powerful tool to model the spectroscopic properties of organic fluorophores. 49,50 In addition, empirical HOSE and BLA models, which successfully correlate the structural features of coumarins to their optoelectronic properties, 47,51 are applied in this study as well.…”

Effect of TiO2particles on normal and resonance Raman spectra of coumarin 343: a theoretical investigation

“…We have investigated several C343 isomers 37 , some of which are denoted as Ca, Cb and Cc as shown in Fig. However, it is a challenge to theoretically construct the suitable interface arrangement because of too many possibilities.…”

“…However, it is a challenge to theoretically construct the suitable interface arrangement because of too many possibilities. It displays that the relative groundstate energies of different isomers are nearly independent of the N-ring conformers (anti-and syn-), and they are basically determined by the -COOH conformers 37 . We have investigated several C343 isomers 37 , some of which are denoted as Ca, Cb and Cc as shown in Fig.…”

Optical and Schottky diode performance of Au/4-hydroxy Coumarin/ITO heterojunction

“…3 shows Raman spectra of current compound. From this plot, weak and strong peaks corresponding to given structure can be observed [19]. For example, C O (in pyrone ring) stretching high-frequency vibrations occur at 1446 cm −1 , 1546 cm −1 , and 1603 cm −1 respectively.…”

“…The intensity of mode with CH 2 wagging and ring skeleton vibration motions (1298 cm −1 ) is relatively weak, but 1302 cm −1 and 1336 cm −1 are strong. The mode with 907 cm −1 corresponds to the out of plane bending of OH whereas the modes with 771 cm −1 are O C C COOH out of plane bending vibration [19]. Fig.…”