Abstract
Neutral/zwitterionic form equilibrium, excited state wave functions, absorption and emission spectra of kynurenine (KN) in various solvents (water, methanol, ethanol, and dimethylsulfoxide) have been studied theoretically. The ground electronic state geometries have been optimized by density functional theory methods; the geometries of the first two singlets excited electronic states have been optimized using the CASSCF technique. The influence of the solvent was taken into account by the calculation of the solvation free energies using the Polarizable Continuum Model (PCM). The spectra of electronic absorption and fluorescence emission have been calculated by the CS-INDO S-CI and SDT-CI methods [Momicchioli, Baraldi, and Bruni, Chem Phys, 1983, 82, 229]. The calculated data reproduce the experimental positions of maxima and the solvent-induced shifts of the absorption and emission bands well. The energy gap between the two lowest excited states of KN increases from aprotic to protic solvents. This fact suggests that the "proximity effect" cannot be responsible for the ultrafast decay of KN fluorescence in protic solvents.
| Original language | English |
|---|---|
| Pages (from-to) | 3799-3804 |
| Number of pages | 6 |
| Journal | International Journal of Quantum Chemistry |
| Volume | 111 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - 15 Nov 2011 |
| Externally published | Yes |
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Keywords
- absorption and emission spectra
- CS-INDO/CI
- DFT calculations
- kynurenine
- PCM model
- proximity effect
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Physical and Theoretical Chemistry
Cite this
Theoretical study of solvent influence on the electronic absorption and emission spectra of kynurenine. / Benassi, Enrico; Sherin, Peter S.
In: International Journal of Quantum Chemistry, Vol. 111, No. 14, 15.11.2011, p. 3799-3804.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Theoretical study of solvent influence on the electronic absorption and emission spectra of kynurenine
AU - Benassi, Enrico
AU - Sherin, Peter S.
PY - 2011/11/15
Y1 - 2011/11/15
N2 - Neutral/zwitterionic form equilibrium, excited state wave functions, absorption and emission spectra of kynurenine (KN) in various solvents (water, methanol, ethanol, and dimethylsulfoxide) have been studied theoretically. The ground electronic state geometries have been optimized by density functional theory methods; the geometries of the first two singlets excited electronic states have been optimized using the CASSCF technique. The influence of the solvent was taken into account by the calculation of the solvation free energies using the Polarizable Continuum Model (PCM). The spectra of electronic absorption and fluorescence emission have been calculated by the CS-INDO S-CI and SDT-CI methods [Momicchioli, Baraldi, and Bruni, Chem Phys, 1983, 82, 229]. The calculated data reproduce the experimental positions of maxima and the solvent-induced shifts of the absorption and emission bands well. The energy gap between the two lowest excited states of KN increases from aprotic to protic solvents. This fact suggests that the "proximity effect" cannot be responsible for the ultrafast decay of KN fluorescence in protic solvents.
AB - Neutral/zwitterionic form equilibrium, excited state wave functions, absorption and emission spectra of kynurenine (KN) in various solvents (water, methanol, ethanol, and dimethylsulfoxide) have been studied theoretically. The ground electronic state geometries have been optimized by density functional theory methods; the geometries of the first two singlets excited electronic states have been optimized using the CASSCF technique. The influence of the solvent was taken into account by the calculation of the solvation free energies using the Polarizable Continuum Model (PCM). The spectra of electronic absorption and fluorescence emission have been calculated by the CS-INDO S-CI and SDT-CI methods [Momicchioli, Baraldi, and Bruni, Chem Phys, 1983, 82, 229]. The calculated data reproduce the experimental positions of maxima and the solvent-induced shifts of the absorption and emission bands well. The energy gap between the two lowest excited states of KN increases from aprotic to protic solvents. This fact suggests that the "proximity effect" cannot be responsible for the ultrafast decay of KN fluorescence in protic solvents.
KW - absorption and emission spectra
KW - CS-INDO/CI
KW - DFT calculations
KW - kynurenine
KW - PCM model
KW - proximity effect
UR - http://www.scopus.com/inward/record.url?scp=80052089082&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80052089082&partnerID=8YFLogxK
U2 - 10.1002/qua.22929
DO - 10.1002/qua.22929
M3 - Article
AN - SCOPUS:80052089082
VL - 111
SP - 3799
EP - 3804
JO - International Journal of Quantum Chemistry
JF - International Journal of Quantum Chemistry
SN - 0020-7608
IS - 14
ER -