Photoinduced intramolecular electron transfer reactions in fullerene-phenothiazine linked compounds: Effects of magnetic field and spacer chain length

Hiroaki Yonemura, Masakazu Noda, Kazuya Hayashi, Hiromasa Tokudome, Shinya Moribe, Sunao Yamada

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Spectroscopic and electrochemical properties of two fullerene(C60)-phenothiazine(PH) linked compounds with different spacer chain length have been compared in benzonitrile (polar solvent) and in benzene (non-polar solvent). Transient absorption and fluorescence spectra indicated that photoinduced intramolecular electron transfer occurred in benzonitrile, but not in benzene. The results are due to solvent effect on energy levels of the photogenerated biradical. The driving forces for the electron transfer were determined by measuring the redox potentials of the C60 and PH moieties. Thermodynamic parameters for the electron transfer processes were evaluated and compared. In benzonitrile, the lifetime of the photo-generated biradical was very long, in spite of being around the top region in Marcus theory. The decay rate of the biradicals was retarded in the presence of magnetic fields. The decay rate constant decreased quickly with increasing the magnetic field and became constant above about 0.2T. The magnetic field effects verified that the triplet biradical was generated by the intramolecular electron transfer from PH to the triplet excited state of C60. The long lifetime is most probably ascribed to the spin multiplicities of the biradical.

Original languageEnglish
Pages (from-to)1395-1403
Number of pages9
JournalMolecular Physics
Volume100
Issue number9
DOIs
Publication statusPublished - May 10 2002

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Molecular Biology
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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