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).
ASJC Scopus subject areas
- Physical and Theoretical Chemistry