Ion-mediated electron transfer in a supramolecular donor-acceptor ensemble

Jung Su Park, Elizabeth Karnas, Kei Ohkubo, Ping Chen, Karl M. Kadish, Shunichi Fukuzumi, Christopher W. Bielawski, Todd W. Hudnall, Vincent M. Lynch, Jonathan L. Sessler

Research output: Contribution to journalArticlepeer-review

163 Scopus citations

Abstract

Ion binding often mediates electron transfer in biological systems as a cofactor strategy, either as a promoter or as an inhibitor. However, it has rarely, if ever, been exploited for that purpose in synthetic host-guest assemblies. We report here that strong binding of specific anions (chloride, bromide, and methylsulfate but not tetrafluoroborate or hexafluorophosphate) to a tetrathiafulvalene calix[4]pyrrole (TTF-C4P) donor enforces a host conformation that favors electron transfer to a bisimidazolium quinone (BIQ 2+) guest acceptor. In contrast, the addition of a tetraethylammonium cation, which binds more effectively than the BIQ2+ guest in the TTF-C4P cavity, leads to back electron transfer, restoring the initial oxidation states of the donor and acceptor pair. The products of these processes were characterized via spectroscopy and x-ray crystallography.

Original languageEnglish
Pages (from-to)1324-1327
Number of pages4
JournalScience
Volume329
Issue number5997
DOIs
StatePublished - 10 Sep 2010

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