Ketonic Defects in Ladder-type Poly(p-phenylene)s
| Autor: | Georg Heimel, Patricia Scandiucci de Freitas, Herbert Wiesenhofer, Lorenz Romaner, Emil List, Ullrich Scherf, Jean-Luc Brédas, Egbert Zojer |
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| Rok vydání: | 2004 |
| Předmět: |
Materials science
Stereochemistry Infrared General Chemical Engineering Infrared spectroscopy Astrophysics::Cosmology and Extragalactic Astrophysics General Chemistry Crystallography Poly(p-phenylene) Molecular vibration Excited state Materials Chemistry Side chain Molecule Astrophysics::Galaxy Astrophysics Excitation |
| Zdroj: | Chemistry of Materials. 16:4667-4674 |
| ISSN: | 1520-5002 0897-4756 |
| Popis: | We investigate the oxidative degradation process occurring in ladder-type poly(p-phenylene) (LPPP) by spectroscopic and quantum-chemical techniques. Annealing experiments carried out for two representatives of the class of LPPP's with different side chains relate the change in emissive behavior of the polymer to the presence of ketonic defects on the main chain. The geometry, excitation, and emission energies as well as vibrational modes are calculated for model LPPP oligomers bearing these defects. The optical properties of these molecules are significantly changed compared to the pristine model systems. In the excited-state geometry, ketone-containing oligomers possess emissive excited states in the energy region of the experimentally observed low-energy emission band. The calculated infrared (IR) absorption peaks associated with the defects can also be correlated with the experimental IR spectra. |
| Databáze: | OpenAIRE |
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