Excitation energy transport processes of porphyrin monomer, dimer, cyclic trimer, and hexamer probed by ultrafast fluorescence anisotropy decay

Hyun Sun Cho, Hanju Rhee, Jae Kyu Song, Chang Ki Min, Masayoshi Takase, Naoki Aratani, Sung Cho, Atsuhiro Osuka, Taiha Joo, Dongho Kim

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Abstract

Femtosecond fluorescence anisotropy measurements for a variety of cyclic porphyrin arrays such as ZnIIporphyrin m-trimer and hexamer are reported along with o-dimer and monomer as reference molecules. In the porphyrin arrays, a pair of porphyrin moieties are joined together via triphenyl linkage to ensure cyclic and rigid structures. Anisotropy decay times of the porphyrin arrays can be well described by the Förster incoherent excitation hopping process between the porphyrin units. Exciton coupling strengths of 74 and 264 cm-1 for the m-trimer and hexamer estimated from the observed excitation energy hopping rates are close to those of B800 and B850, respectively, in the LH2 bacterial light-harvesting antenna. Thus, these cyclic porphyrin array systems have proven to be useful in understanding energy migration processes in a relatively weak interaction regime in light of the similarity in overall structures and constituent chromophores to natural light-harvesting arrays.

Original languageEnglish
Pages (from-to)5849-5860
Number of pages12
JournalJournal of the American Chemical Society
Volume125
Issue number19
DOIs
Publication statusPublished - 2003 May 14

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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