08 Fakultät Mathematik und Physik

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/9

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Institute: search.filters.UBSInstitut.Institut für Organische ChemieEnd date: 1999

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Now showing 1 - 6 of 6
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    Intramolecular energy transfer through linear polyenes : effect of spacers
    (1990) Blessing, Gerd; Holl, Norbert; Port, Helmut; Wolf, Hans Christoph; Effenberger, Franz; Kesmarszky, Thomas; Schlosser, Hubert
    The optical properties of linear polyenes terminally substituted with different molecules (mainly anthryl- and TPP-substituents) have been studied. Bicyclic spacers within the polyene chain affect the quantum yields but do not interrupt intramolecular energy transfer between the endgroups.
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    Dual fluorescence of 9-anthryl-substituted oligothiophenes in nonpolar environment
    (1994) Emele, Peter; Meyer, Dirk U.; Holl, Norbert; Port, Helmut; Wolf, Hans Christoph; Würthner, Frank; Bäuerle, Peter; Effenberger, Franz
    9-Anthryl-oligothiophenes (9A-Tn, n = 1–4) have been studied in n-hexane solution between helium and room temperature using absorption, fluorescence emission and excitation spectra and time resolved fluorescence measurements. These compounds are reference systems for studies on intramolecular energy and charge transfer in donor/acceptor-substituted conjugated chain molecules. The absorption spectra show contribution of both substituents anthracene and oligothiophene, but no additional bands due to mixed electronic states. Dual fluorescence is observed at Tgreater-or-equal, slanted 120 K for the compounds 9A-Tn (n = 1–3), but not for 9A-T4. Time resolved spectroscopy reveals a dynamical coupling between the two emission components whose relative quantum yields are strongly temperature dependent. The occurrence of the dual fluorescence is explained by an intramolecular torsional motion between the two molecular subunits.
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    Energy transfer through conjugated polyenes
    (1989) Maier, Stefan; Port, Helmut; Wolf, Hans Christoph; Effenberger, Franz; Schlosser, Hubert
    From an analysis of absorption, fluorescence and excitation spectra of linear polyene molecules with 4 to 13 double bonds and one or two aromatic substituents at the chain ends we conclude that the aromatic substituents can be excited individually, and that intramolecular energy transfer from one end group via the polyene to the other end group is possible.
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    Synthesis and optical properties of terminally substituted conjugated polyenes
    (1988) Effenberger, Franz; Schlosser, Hubert; Bäuerle, Peter; Maier, Stefan; Port, Helmut; Wolf, Hans Christoph
    Long-chain, conjugated polyenes can function as molecular wires. This is shown by the photophysical properties of polyenes containing naphthyl, anthryl, and tetraphenylporphyrinyl (TPP) terminal groups. When the anthryl group in 1, which is obtainable by a sequence of Wittig reactions, is selectively excited, strong TPP emission is observed.
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    Terminally substituted conjugated polyenes : synthesis and energy transfer properties
    (1991) Effenberger, Franz; Wolf, Hans Christoph
    The present publication summarizes the results of our investigations on conjugated polyenes with different end groups. The spectroscopic data reveal the possibi~ity of a selective electronic end group excitation in the conjugated systems influenced by steric factors between the end groups and polyene chains. An intramolecular energy transfer from one excited terminal substituent to the other via the polyene chain is likely. The interruption of the conjugation in the polyenes by a bicycloalkane unit results in a separation of the molecules' spectroscopic behavior. Energy transfer is modified, but still present.
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    Fulgides as switches for intramolecular energy transfer
    (1993) Walz, Jochen; Ulrich, Karl; Port, Helmut; Wolf, Hans Christoph; Wonner, Johann; Effenberger, Franz
    In a molecular unit which is a donor-fulgimide-acceptor triade, the possibility of an intramolecular energy transfer from donor to acceptor depends upon the isomer configuration of the photochromic fulgimide. It is shown that a switching on and off of this intramolecular energy transfer is possible by photoinduced shifting of the fulgimide levels between a trap and an antitrap function.