Ultrafast photoinduced electron transfer between an incarcerated donor and a free acceptor in aqueous solution

Mintu Porel, Chi Hung Chuang, Clemens Burda, Vaidhyanathan Ramamurthy

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Supramolecular photoinduced electron transfer dynamics between coumarin 153 (C153) and 4,4′-dimethyl viologen dichloride (MV2+) across the molecular barrier of a host molecule, octa acid (OA), has been investigated with femtosecond time resolution. The ultrafast electron transfer from C153 to MV2+ followed excitation with 150 fs laser pulses at a wavelength of 390 nm despite the fact that C153 was incarcerated within an OA2 capsule. As a result, the photoexcited coumarin did not show any of the typical relaxation dynamics that is usually observed in free solution. Instead, the excited electron was transferred across the molecular wall of the capsuleplex within 20 ps. Likewise, the lifetime of the charge transfer state was short (724 ps), and electron back-transfer reestablished the ground state of the system within 1 ns, showing strong electronic coupling among the excited electron donor, host, and acceptor. When the donor was encapsulated into the host molecule, the electron transfer process showed significantly accelerated dynamics and essentially no solvent relaxation compared with that in free solution. The study was also extended to N-methylpyridinium iodide as the acceptor with similar results.

Original languageEnglish (US)
Pages (from-to)14718-14721
Number of pages4
JournalJournal of the American Chemical Society
Issue number36
StatePublished - Sep 12 2012

ASJC Scopus subject areas

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


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