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Synthesis, Spectroscopy, Nonlinear Optics, and Theoretical Investigations of Thienylethynyl Octopoles with a Tunable Core
Author(s) -
Oliva María Moreno,
Casado Juan,
López Navarrete Juan T.,
Hennrich Gunther,
van Cleuvenbergen Stijn,
Asselberghs Inge,
Clays Koen,
Ruiz Delgado M. Carmen,
Brédas JeanLuc,
Seixas de Melo J. Sérgio,
De Cola Luisa
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200900702
Subject(s) - intersystem crossing , phosphorescence , excited state , photochemistry , spectroscopy , molecule , chemistry , absorption spectroscopy , fluorescence , internal conversion , acceptor , ultrafast laser spectroscopy , spectral line , atomic physics , molecular physics , singlet state , optics , physics , organic chemistry , quantum mechanics , astronomy , condensed matter physics
We have synthesized three new molecules that have three thienylethynyl arms substituting a central benzene core and different electron donor/acceptor groups in the three remaining phenyl positions. The absorption, fluorescence, phosphorescence, and transient triplet–triplet spectra are analyzed in the light of the electronic structure of the ground and excited states obtained from quantum‐chemical calculations. From the above, the relevant photophysical data (including quantum yields, lifetimes, and rate constants) could be derived. It was found that the major deactivation pathway is internal conversion, which competes with the fluorescence and intersystem crossing processes. For the three investigated compounds, we provide convincing theoretical support corroborating these findings and further conclusions based on the theoretical information obtained. These molecules are one of the very few cases in which the depolarization ratios, obtained from the NLO optical measurements, clearly reflect the octopolar configuration. Molecular hyperpolarizabilities have been measured and display a typical dependence on the donor–acceptor substitution pattern.