Dresden 2011 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 21: Electronic Spectroscopy I
MO 21.7: Vortrag
Donnerstag, 17. März 2011, 12:00–12:15, MER 02
Mono-hydroxy[2.2]paracyclophane: a model compound for strongly interacting π-systems — •Christof Schon, Wolfgang Roth, Ingo Fischer, Johannes Pfister, Reinhold F. Fink, and Bernd Engels — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
Paracyclophane-based materials have been suggested for applications in organic solar cells, organic thin film transistors and organic light emitting diodes due to their photophysical properties and their high electric conductivity. Paracyclophane molecules have conjugated ring systems and the rings are rigidly connected by bridges. Therefore, they are suitable model systems for studying the interaction between cofacially oriented π-moieties. In recent years, paracyclophanes with two identical π-moieties (e.g. two benzene or two phenol moieties) have been investigated in detail. Now, we have investigated an isomer with different π-moieties (one benzene and one phenol moiety): monohydroxy[2.2]paracyclophane (MHPC). In the REMPI spectrum the electronic origin of MHPC is at 30772 cm−1. We observe rich vibronic progressions. The experimental results were interpreted on the basis of ab initio calculations of the electronic ground state (SCS-MP2) and the lowest excited state (SCS-CC2). The ground state potential curve of MHPC shows a single minimum. In the first excited state a double minimum potential along the twist coordinate was calculated. This is an indication of an experimentally observed progression with inverse anharmonicity. Overall an excellent agreement between experiment and theory is observed.