Two-Electron Reduction of [{(bpy)2Ru(dmbbbpy)}3Ru]8+ from (BNA)2 via Photoinduced Electron Transfer [dmbbbpy = 2,2′-Bis(N-methylbenzimidazole-2-yl)-4,4′-bipyridine]
Abstract
Photoirradiation (λ > 500 nm) of [{(bpy)2Ru(dmbbbpy)}3Ru]8+ (18+) (dmbbbpy = 2,2′-bis(N-methylbenzimidazole-2-yl)-4,4′-bipyridine and bpy = 2,2′-bipyridine) in the presence of dimeric N-benzyldihydronicotinamide, (BNA)2, produced stable two-electron reduced species (16+). Laser flash photolysis and emission spectroscopy were used to understand the reductive reaction pathways. The emission quenching kq value (4.1 × 1099 M-1 s-1) obtained from Stern-Volmer plot is in excellent agreement with the electron-transfer rate constant, ket (4.7 × 109 M-1 s-1) determined from the decay kinetics of transient 318+ triplet-triplet absorption at 650 nm indicating that photoreduction of 18+ proceeds via photoinduced electron transfer from (BNA)2 to 318+*. After bimolecular electron-transfer process, 18+ was reduced to 17+ and the electron donor (BNA)2 was oxidized. Oxidation of (BNA)2 leads to the formation of highly reactive species, BNA· which then reduces 17+ to 16+. The quantum yield for the formation of the photoreduction product was 0.026.
Publication Title
Inorganic Chemistry
Recommended Citation
Ali, M., Sato, H., Haga, M., Tanaka, K., Yoshimura, A., & Ohno, T. (1998). Two-Electron Reduction of [{(bpy)2Ru(dmbbbpy)}3Ru]8+ from (BNA)2 via Photoinduced Electron Transfer [dmbbbpy = 2,2′-Bis(N-methylbenzimidazole-2-yl)-4,4′-bipyridine]. Inorganic Chemistry (24), 6176-6180. https://doi.org/10.1021/ic980586e
