Photoinduced electron transfer in tetrathiafulvalene-porphyrin-fullerene molecular triads

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

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

The two molecular triads 1a and 1b consisting of a porphyrin (P) covalently linked to a fullerene (C60) electron acceptor and tetrathiafulvalene (TTF) electron-donor moiety were synthesized, and their photochemical properties were determined by transient absorption and emission techniques. Excitation of the freebase-porphyrin moiety of the TTF-P2H-C60 triad 1a in tetrahydro-2-methylfuran solution yields the porphyrin first excited singlet state TTF-1P2H-C60, which undergoes photoinduced electron transfer with a time constant of 25 ps to give TTF-P2H·+-C60·-. This intermediate charge-separated state has a lifetime of 230 ps, decaying mainly by a charge-shift reaction to yield a final state, TTF·+-P2H-C60·-. The final state has a lifetime of 660 ns, is formed with an overall yield of 92%, and preserves ca. 1.0 eV of the 1.9 eV inherent in the porphyrin excited state. Similar behavior is observed for the zinc analog 1b. The TTF-PZn·+-C60·- state is formed by ultrafast electron transfer from the porphyrinatozinc excited singlet state with a time constant of 1.5 ps. The final TTF·+-PZn-C60·- state is generated with a yield of 16%, and also has a lifetime of 660 ns. Although charge recombination to yield a triplet has been observed in related donor-acceptor systems, the TTF·+-P-C60·- states recombine to the ground state, because the molecule lacks low-energy triplet states. This structural feature leads to a longer lifetime for the final charge-separated state, during which the stored energy could be harvested for solar-energy conversion or molecular optoelectronic applications.

Original languageEnglish
Pages (from-to)2765-2783
Number of pages19
JournalHelvetica Chimica Acta
Volume84
Issue number9
DOIs
Publication statusPublished - 2001

ASJC Scopus subject areas

  • Catalysis
  • Biochemistry
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Fingerprint Dive into the research topics of 'Photoinduced electron transfer in tetrathiafulvalene-porphyrin-fullerene molecular triads'. Together they form a unique fingerprint.

  • Cite this