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- Han, W. G., et al.
(author)
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A theoretical study of the UV/visible absorption and emission solvatochromic properties of solvent-sensitive dyes
- 2003
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In: ChemPhysChem. - : Wiley. - 1439-4235 .- 1439-7641. ; 4:10, s. 1084-1094
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Journal article (peer-reviewed)abstract
- Using the density-functional vertical self-consistent reaction field (VSCRF) solvation model, incorporated with the conductor-like screening model (COSMO) and the self-consistent reaction field (SCRF) methods, we have studied the solvatochromic shifts of both the absorption and emission bands of four solvent sensitive dyes in different solutions. The dye molecules studies here are: S-TBA merocyanine, Abdel-Halim's merocyanine, the rigidified amino-coumarin C153, and Nile red. These dyes were selected because they exemplify different structural features likely to impact the solvent-sensitive fluorescence of push-pull, or merocyanine, fluorophores. All trends of the blue or red shifts were correctly predicted, comparing with the experimental observations. Explicit h-bonding interactions were also considered in several protic solutions like H2O, methanol and ethanol, showing that including explicit H-bonding solvent molecule(s) in the calculations is important to obtain the correct order of the excitation and emission energies. The geometries, electronic structures, dipole moments, and intra- and intermolecular charge transfers of the dyes in different solvents are also discussed.
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- Liu, T. Q., et al.
(author)
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Density functional vertical self-consistent reaction field theory for solvatochromism - Studies of solvent-sensitive dyes
- 2004
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In: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 108:16, s. 3545-3555
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Journal article (peer-reviewed)abstract
- On the basis of the Franck-Condon principle, a density functional vertical self-consistent reaction field (VSCRF) solvation model for vertical excitation and emission processes is established. The principles and implementation of the VSCRF model are presented. The predicted blue shifts of the vertical excitation energies of diazines in different solvents from n-heptane to water solutions are compared with the corresponding time dependent density functional calculations and are in very good agreement with experiment. We have also applied this method to predict the blue shifts and the vertical excitation and emission energies of Brooker's merocyanine dye with increasing solvent polarities from CHCI3 to H2O solutions. Overall, our calculations predicted the relative excitation and emission energy orderings for Brooker's merocyanine in different solvents with different polarities. Also, the calculated Stokes shift is fairly well represented for different solvents, and the calculations correctly show that the absorption energies have a much stronger solvent dependence than the emission energies. The importance of both relaxation of the molecular structures and consideration of explicit H-bonding H2O and CH3OH molecules in water and methanol solvents in predicting the solvatochromic shifts is also discussed.
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