Benzene-templated model systems for photosynthetic antenna-reaction center function

Paul A. Liddell, Gerdenis Kodis, Linda De La Garza, Ana Moore, Thomas Moore, Devens Gust

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Abstract

A synthetic strategy for preparing artificial photosynthetic antenna-reaction center complexes based on formation of a benzene core via a Diels-Alder reaction has been applied to the preparation of a zinc porphyrin (P zn)-free base porphyrin (P 2H-fullerene (C 60) molecular triad. Spectroscopic studies in 2-methyltetrahydrofuran show that excitation of the zinc porphyrin antenna moiety to form 1P zn-P 2H-C 60 is followed by singlet-singlet energy transfer to the free base porphyrin excitation energy trap (τ = 59 ps), yielding P Zn- 1P 2H-C 60. The free base porphyrin first excited singlet state decays by photoinduced electron transfer to the fullerene (τ = 25 ps), producing a P zn-P 2H .+-C 60 .- charge-separated state. Charge shift (τ = 167 ps) yields P zn .+-P 2H-C 60 .-. This final charge-separated state is formed with quantum yields >90% following excitation of any of the three chromophores. Charge recombination in 2-methyltetrahydrofuran (τ = 50 ns) occurs by an apparently endergonic process to give triplet states of the chromophores, rather than the ground state. In benzonitrile, charge recombination yields the ground state (τ = 220 ns). The high efficiencies of the various energy and electron-transfer processes suggest that this molecular architecture will be useful for the design of more complex antenna-reaction center complexes.

Original languageEnglish (US)
Pages (from-to)10256-10265
Number of pages10
JournalJournal of Physical Chemistry B
Volume108
Issue number29
DOIs
StatePublished - Jul 22 2004

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Benzene-templated model systems for photosynthetic antenna-reaction center function. / Liddell, Paul A.; Kodis, Gerdenis; De La Garza, Linda; Moore, Ana; Moore, Thomas; Gust, Devens.

In: Journal of Physical Chemistry B, Vol. 108, No. 29, 22.07.2004, p. 10256-10265.

Research output: Contribution to journalArticle