title: Excited state electron transfer after visible light absorption by the Co(I) state of vitamin B12.
abstract: The first example of excited state electron transfer from cob(I)alamin is reported herein. Vitamin B12 was anchored to a mesoporous TiO2 thin film and electrochemically reduced to the cob(I)alamin form. Pulsed laser excitation resulted in rapid excited state electron transfer, ket > 10(8) s(-1), followed by microsecond interfacial charge recombination to re-form cob(I)alamin. The supernucleophilic cob(I)alamin was found to be a potent photoreductant. The yield of excited state electron transfer was found to be excitation wavelength dependent. The implications of this dependence are discussed.
authors.affiliation: Department of Physical Sciences, Kutztown University, 15200 Kutztown Rd, Kutztown, Pennsylvania, USA.
authors.forename: Darren
authors.initials: D
authors.lastname: Achey
authors.forename: Erinn C
authors.initials: EC
authors.lastname: Brigham
authors.forename: Brian N
authors.initials: BN
authors.lastname: DiMarco
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Meyer
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D004579:Electron Transport; D008027:Light; D011789:Quantum Theory; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D003035:Cobalt; D014805:Vitamin B 12