Photoejection of electrons from cycloocta[1,2,3,4-def;5,6,7,8-d′ e′ f′]bisbiphenylene radical-anion and dianion derivatives: Identification of a light-induced disproportionation

Roy Shenhar, Itamar Willner, Andrzej Rajca, Mordecai Rabinovitz

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Photoejection of electrons from 2,5,8,11-tetra-tert-butylcycloocta[1,2,3,4-def;5,6,7,8-d′ e′ f′]bisbiphenylene radical anion, BPḊ-, and the respective dianion, BPD2-, are described. Photoejection of an electron from BPD2- yields a [BPḊ-⋯e-] cage complex and separated BPḊ- and e-/Li+ species. Recombination of the cage photoproducts proceeds at room temperature with a rate constant of krec1 = (7.0 ± 0.2) × 105 s-1, and the separated photoproducts recombine by a diffusional back-electron-transfer rate constant of krec2 = (1.5 ± 0.2) × 109 M-1̇s-1. Photoejection of the electron from BPḊ- yields the neutral π-system, and the ejected electron reduces an unreached BPḊ- to form BPD2-. The photoejection of the electron from BPḊ- thus yields the disproportionation products, BPD and BPD2-. The disproportionation products recombine by a diffusional process, krec = (1.0 ± 0.2) × 1010 M-1̇s-1 (at room temperature).

Original languageEnglish (US)
Pages (from-to)6206-6212
Number of pages7
JournalJournal of Physical Chemistry A
Issue number25
StatePublished - Jun 27 2002


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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