Starostin, R.O.; Freidzon, A.Y.; Gromov, S.P. Theoretical Study of Structure and Photophysics of Homologous Series of Bis(arylydene)cycloalkanones. Int. J. Mol. Sci.2023, 24, 13362.
Starostin, R.O.; Freidzon, A.Y.; Gromov, S.P. Theoretical Study of Structure and Photophysics of Homologous Series of Bis(arylydene)cycloalkanones. Int. J. Mol. Sci. 2023, 24, 13362.
Starostin, R.O.; Freidzon, A.Y.; Gromov, S.P. Theoretical Study of Structure and Photophysics of Homologous Series of Bis(arylydene)cycloalkanones. Int. J. Mol. Sci.2023, 24, 13362.
Starostin, R.O.; Freidzon, A.Y.; Gromov, S.P. Theoretical Study of Structure and Photophysics of Homologous Series of Bis(arylydene)cycloalkanones. Int. J. Mol. Sci. 2023, 24, 13362.
Abstract
Photophysical properties of a series of bis(arylydene)cycloalkanone dyes with various donor substituentns are studied by quantum chemistry. Their capacity for luminescence and nonradiative relaxation through trans-cis isomerization is related to their structure, in particular, to the donor capacity of the substituents and the degree of conjugation due to the central cycloalkanone moiety. It is shown that cyclohexanone central moiety introduces distortions and disrupts the conjugation, thus leading to a nonmonotonic change in their properties. The increasing donor capacity of the substituents causes increase in the HOMO energy (raise of the oxidation potential) and decrease in the HOMO-LUMO gap, which results in the red shift of the absorption spectra. The ability of the excited dye to relax through fluorescence or through trans-cis isomerization is governed by the height of the barrier between the Franck–Condon and S1-S0 conical intersection regions on the potential energy surface of the lowest π-π* excited state. This barrier also correlates with the donor capacity of the substituents and the degree of conjugation between the central and donor moieties. The calculated fluorescence and trans-cis isomerization rates are in good agreement with the observed fluorescence quantum yields.
Keywords
bis(arylydene)cycloalkanone dyes; photophysical properties; photochemical properties; absorption; luminescence; trans-cis isomerization; quantum chemistry; density functional theory; potential energy surface; conical intersection
Subject
Chemistry and Materials Science, Theoretical Chemistry
Copyright:
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