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BP: Fachverband Biologische Physik
BP 16: Poster Session I
BP 16.8: Poster
Dienstag, 27. März 2007, 17:00–19:30, Poster D
Energy transfer processes in a bisporphyrinic switch — •Jedrzej Szmytkowski1,3, Robert Hauschild1, Manfred Scholdt1, Teodor Silviu Balaban2,3, and Heinz Kalt1,3 — 1Univesität Karlsruhe (TH), Karlsruhe, Germany — 2Forschungszentrum Karlsruhe, Institute for Nanotechnology, Karlsruhe, Germany — 3Center for Functional Nanostructures (CFN), Karlsruhe, Germany
Energy transfer processes are the first step in light-harvesting and have been optimized in photosynthetic organisms. Artificial mimics are essential in understanding and controlling the efficiency with which after photon capture an energetic trap can be accessed. We have studied various bis-porphyrinic constructs, covalently attached to spacers such as a rigid steroidal skeleton or a terpyridine capable of undergoing a conformational switch from an extended "W" conformation into a more compact "U" form. The switching can be performed by addition of coordinating metals or of ditopic ligands. Singlet-singlet energy transfer was put into evidence by time-resolved fluorescence and the data have been analyzed using decay associated spectra (DAS). While in the steroidal systems a Förster-type energy transfer occurs, the rate and efficiency of the energy transfer can be influenced by the added ligand in the terpyridinc constructs.