title: Photoinduced biphasic hydrogen evolution: decamethylosmocene as a light-driven electron donor.
abstract: Excitation of the weak electron donor decamethylosmocene on illumination with white light produces an excited-state species capable of reducing organically solubilized protons under biphasic conditions. Insight into the mechanism and kinetics of light-driven biphasic hydrogen evolution are obtained by analysis with gas chromatography, cyclic voltammetry, and UV/Vis and (1)H NMR spectroscopy. Formation of decamethylosmocenium hydride, which occurs prior to hydrogen evolution, is a rapid step relative to hydrogen release and takes place independently of light activation. Remarkably, hydride formation occurs with greater efficiency (ca. 90% conversion) under biphasic conditions than when the reaction is carried out in an acidified single organic phase (ca. 20% conversion). Cyclic voltammetry studies reveal that decamethylosmocene has a higher proton affinity than either decamethylferrocene or osmocene.
authors.affiliation: Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, 1015 Lausanne, Switzerland.
authors.forename: Peiyu
authors.initials: P
authors.lastname: Ge
authors.forename: Astrid J
authors.initials: AJ
authors.lastname: Olaya
authors.forename: Micheál D
authors.initials: MD
authors.lastname: Scanlon
authors.forename: Imren
authors.initials: I
authors.lastname: Hatay Patir
authors.forename: Heron
authors.initials: H
authors.lastname: Vrubel
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D055664:Electrochemical Techniques; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry*; D008027:Light; D009942:Organometallic Compounds / Q000737:chemistry*; D055668:Photochemical Processes
chemical_list: D009942:Organometallic Compounds; D006859:Hydrogen
keywords: electrochemistry; hydrogen evolution reaction; interfaces; metallocenes; photochemistry