Ketonic defects in ladder-type poly(p-phenylene)s

Lorenz Romaner, Georg Heimel, Herbert Wiesenhofer, Patricia Scandiucci De Freitas, Ullrich Scherf, Jean Luc Brédas, Egbert Zojer, Emil J.W. List

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)4667-4674
Number of pages8
JournalChemistry of Materials
Issue number23
StatePublished - Nov 16 2004
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry


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