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| Item type: | Article | ||||
|---|---|---|---|---|---|
| Journal or Publication Title: | Polish Journal of Chemistry | ||||
| Volume: | 82 | ||||
| Number of Issue or Book Chapter: | 4 | ||||
| Page Range: | pp. 773-793 | ||||
| Date: | 2008 | ||||
| Additional Information (public): | CAN 148:471497 22-9 Physical Organic Chemistry 1197-19-9 (DMABN) Role: PRP (Properties) (N-phenylpyrrole vs.; conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); 635-90-5 (N-Phenylpyrrole) Role: PRP (Properties) (conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); 71-43-2D (Benzene) Role: PRP (Properties) (model for; conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.) | ||||
| Institutions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Bernhard Dick | ||||
| Identification Number: |
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| Keywords: | Radical ions (anions, conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); Charge transfer state; Dipole moment; Electronic structure; Excited singlet state; Internal rotation; MCSCF; Potential energy hypersurface; Rotamers; Substituent effects (conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); Fluorescence (dual, conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); Conformational transition (internal rotation, conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); Electron transfer (intramol., conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); Jahn-Teller effect (quasi-, conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); Bond angle (torsional, conical intersections and electronic structure of excited states of N-phenylpyrrole as prototypical dual fluorescence mol.); conical intersection electronic structure phenylpyrrole prototype mol exhibiting fluorescence | ||||
| Dewey Decimal Classification: | 500 Science > 540 Chemistry & allied sciences | ||||
| Status: | Published | ||||
| Refereed: | Yes, this version has been refereed | ||||
| Created at the University of Regensburg: | Partially | ||||
| Item ID: | 5551 |
Abstract
The mechanism leading to dual fluorescence in substituted benzene derivs. is discussed using N-Ph pyrrole (PP) as a test mol. A model based on the quasi-Jahn-Teller distortion of the charge transfer (CT) state of PP, similar to that of the benzene anion radical, is presented. The model helps to locate stationary points on the S1 singlet excited state potential surface, and to construct an energy ...
Abstract
The mechanism leading to dual fluorescence in substituted benzene derivs. is discussed using N-Ph pyrrole (PP) as a test mol. A model based on the quasi-Jahn-Teller distortion of the charge transfer (CT) state of PP, similar to that of the benzene anion radical, is presented. The model helps to locate stationary points on the S1 singlet excited state potential surface, and to construct an energy level diagram. The energy and structure of the quasi Jahn-Teller degeneracy which is between S3 and S2 are computed, as well as those of three conical intersections connecting S1 and S2. The findings indicate a complex nature of the S1 state electronic state, contg. several local min., stationary points and surface crossings. The major structural change responsible for the stabilization of the CT state is the ring quinoid deformation which is a main component of the energy difference gradient vector in the branching space of all S1/S2 conical intersections. In the resulting charge transfer state (which is of quinoid structure) the pyrrole ring can either rotate to form a stabilized twisted species, or remain planar depending on substitution. This result holds also for DMABN and other mols. in which the donor is a substituted amine moiety. It is concluded, in line with a recent study on DMABN that the TICT and PICT models are not mutually exclusive, but two different manifestations of the same phys. reality.
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