Co-facial magnesium porphyrin dimer complexed with fullerene: Photosynthetic reaction center model of 'special pair' self-assembled to electron acceptor

Atula S.D. Sandanayaka, Navaneetha K. Subbaiyan, Raghu Chitta, Yasuyuki Araki, Osamu Ito, Francis D'Souza

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Using a self-assembled supramolecular approach, a closer model for the photosynthetic reaction center 'special pair' assembled with an electron acceptor conjugate, is reported. As the 'special pair' donor, magnesium meso-(benzo-15-crown-5)porphyrin was self-assembled with K+ to form a highly stable Mg porphyrin dimer with a co-facial geometry arrangement, which is a better electron donor since it is nearly 130 mV easier to oxidize compared to the earlier reported Zn porphyrin dimer analog. Further, pyridine and alkyl ammonium cation-functionalized fullerene was attached via axial coordination and crown ether-alkyl ammonium cation complexation to form the four-fold, donor-acceptor complex. The self-assembled supramolecular complex, constructed using this approach, possesses defined geometry and orientation. Efficient charge separation from the singlet excited state of the Mg porphyrin dimer to the fullerene entity and a relatively slow charge recombination, were revealed by time-resolved emission and nanosecond transient absorption spectral studies, supporting the impending exploitation of these novel biomimetic model systems for light energy harvesting applications.

Original languageEnglish
Pages (from-to)857-865
Number of pages9
JournalJournal of Porphyrins and Phthalocyanines
Volume12
Issue number7
DOIs
Publication statusPublished - 2008

Keywords

  • Biomimicry
  • Fullerene
  • Magnesium porphyrin
  • Photoinduced electron transfer
  • Synthetic reaction center

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