Efficient multistep photoinitiated electron transfer in a molecular pentad

John Devens Gust, Thomas A Moore, Ana L Moore, Seung Joo Lee, Edith Bittersmann, David K. Luttrull, Aden A. Rehms, Janice M. Degraziano, Xiaochun C. Ma, Feng Gao, Robert E. Belford, Todd T. Trier

Research output: Contribution to journalArticle

222 Citations (Scopus)

Abstract

A synthetic five-part molecular device has been prepared that uses a multistep electron transfer strategy similar to that of photosynthetic organisms to capture light energy and convert it to chemical potential in the form of long-lived charge separation. It consists of two covalently linked porphyrin moieties, one containing a zinc ion (Pzn) and the other present as the free base (P). The metallated porphyrin bears a carotenoid polyene (C) and the other a diquinone species (QA-QB). Excitation of the free-base porphyrin in a chloroform solution of the pentad yields an initial charge-separated state, C-PZn-P•+-QA•--Q B, with a quantum yield of 0.85. Subsequent electron transfer steps lead to a final charge-separated state, C•+-PZn-P-QA-QB •-, which is formed with an overall quantum yield of 0.83 and has a lifetime of 55 microseconds. Irradiation of the free-base form of the pentad, C-P-P-QA-QB, gives a similar charge-separated state with a lower quantum yield (0.15 in dichloromethane), although the lifetime is increased to ∼340 microseconds. The artificial photosynthetic system preserves a significant fraction (∼1.0 electron volt) of the initial excitation energy (1.9 electron volts) in the long-lived, charge-separated state.

Original languageEnglish
Pages (from-to)199-201
Number of pages3
JournalScience
Volume248
Issue number4952
Publication statusPublished - Apr 13 1990

    Fingerprint

ASJC Scopus subject areas

  • General

Cite this

Gust, J. D., Moore, T. A., Moore, A. L., Lee, S. J., Bittersmann, E., Luttrull, D. K., ... Trier, T. T. (1990). Efficient multistep photoinitiated electron transfer in a molecular pentad. Science, 248(4952), 199-201.