Photoinduced electron and proton transfer in the hydrogen-bonded pyridine - Pyrrole system

Journal of Physical Chemistry B

Volumn 111, Issue 22, 2007, Pages 6110-6112

  Frutos, Luis Manuel ^a,c   Markmann, Andreas ^a   Sobolewski, Andrzej L ^b   Domcke, Wolfgang ^a  

^a TECHNICAL UNIVERSITY OF MUNICH   (Germany)

^b INSTITUTE OF PHYSICS   (Poland)

^c UNIVERSITY OF ALCALÁ   (Spain)

Author keywords

[No Author keywords available]

Indexed keywords

DNA; ELECTRON TRANSITIONS; HYDROGEN BONDS; PROTON TRANSFER;

GEOMETRIC STRUCTURE; PHOTOINDUCED ELECTRON; PYRROLE SYSTEM;

PYRIDINE;

EID: 34250786279     PISSN: 15206106     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp0729361     Document Type: Article

References (17)

1. (a) Sobolewski, A. L.; Domcke, W. Phys. Chem. Chem. Phys. 2004, 6, 2763-2771.
2. (b) Sobolewski, A. L.; Domcke, W.; Hättig, C. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 17903-17906.
3. (c) Perun, S.; Sobolewski, A. L.; Domcke, W. J. Phys. Chem. A 2006, 110, 9031-9038.
4. (a) Schultz, T.; Samoylova, E.; Radloff, W.; Hertel, I. V.; Sobolewski, A. L.; Domcke, W. Science 2004, 306, 1765-1768.
5. (b) AboRiziq, A.; Grace, L.; Nir, E.; Kabelac, M.; Hobza, P.; de Vries, M. S. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 20-23.
6. (c) Sobolewski, A. L.; Domcke, W. Europhys. News 2006, 37, 20-23.
7. Nir, E.; Kleinermanns, K.; de Vries., M. S. Nature 2000, 408, 949-951.
8. (a) Douhal, A.; Kim, S. K.; Zewail, A. H. Nature 1995, 578, 260-263.
9. (b) Frey, J. A.; Müller, A.; Frey, H.-A.; Leutwyler, S. J. Chem. Phys. 2004, 121, 8237-8245.
10. All calculations were performed at the CASSCF(12,11)/6-31G(d) level of theory, and single-point CASPT2 calculations were performed. Active space was selected to include all π orbitals. CASSCF gradient and frequency calculations were performed with Gaussian 03 (see http://www.gaussian.com/) and CASPT2 single-point calculations with MOLCAS, version 6 (see http://www.teokem.lu.se/molcas/). See the Supporting Information for complete references.
11. iππ* state, since it has a higher oscillator strength than the π* states and is expected to be the more efficiently populated state in DNA base pairs. See: Merchan, M.; Serrano-Andres, L. J. Am. Chem. Soc. 2003, 125, 8108-8109.
12. 1πiπ* excited state corresponds mainly to pyridine excitation. The energy of this state is in good agreement with previous CASPT2 results for isolated pyridine. See: Lorentzon, J.; Fülscher, M. P.; Roos, B. O. Theor. Chim. Acta 1995, 92, 67-81.
13. Since the pyridine and pyrrole moieties are weakly coupled, the π Orbitals are localized on either pyridine or pyrrole. The excited states can therefore be classified as locally excited states (on pyridine or pyrrole) or charge-transfer states.
14. The GD vector gives the molecular distortion of steepest gradient of the energy difference between the adiabatic PESs involved in the crossing, while the DC vector gives the molecular distortion corresponding to the maximum coupling between the states. In the case of the 82/81 AC, the two vectors are parallel (see the Supporting Information for details).
15. An AC also has been proposed for an intramolecular triplet-triplet energy-transfer process, the mechanism of which is closely related to electron-transfer processes. See: Frutos, L. M.; Sancho, U.; Castafio, O. J. Phys. Chem. A 2005, 109, 2993-2995.
16. -1 at the CASPT2 level.
17. A secondary energy minimum on the ground state corresponding to the proton i attached to the pyridine molecule was located. This intermediate is metastable and has an extremely low energy of activation (ca. 1 kcal/mol) for relaxation to the global minimum.