title: In situ nanostructure formation of (micro-hydroxo)bis(micro-carboxylato) diruthenium units in nafion membrane and its utilization for selective reduction of nitrosonium ion in aqueous medium.
abstract: Nanostructured molecular film containing the (micro-hydroxo)bis(micro-carboxylato) diruthenium(III) units, [RuIII2(micro-OH)(micro-CH3COO)2(HBpz3)2]+ ({RuIII2(micro-OH)}), was prepared by an in situ conversion of its micro-oxo precursor, [RuIII2(micro-O)(micro-CH3COO)2(HBpz3)2] ({RuIII2(micro-O)}), in a Nafion membrane matrix, where HBpz3 is hydrotris(1-pyrazolyl)borate. The conversion procedure results in fine nanoparticle aggregates of the {RuIII2(micro-OH)} units in the Nafion membrane (Nf-{RuIII2(micro-OH)}), where an average particle size (4.1 +/- 2.3 nm) is close to the Nafion's cluster dimension of approximately 4 nm. Chemically modified electrodes by using the Nafion molecular membrane films (Nf-{RuIII2(micro-OH)}-MMFEs) were further developed on ITO/glass and glassy carbon electrode (GCE) surfaces, and a selective reduction of nitrosonium ion (NO+), presumably through reaction of a {RuIIRuIII(micro-OH)} mixed-valence state with HNO2, was demonstrated without interference by molecular oxygen in an acidic aqueous solution. The Nf-{RuIII2(micro-OH)}-MMFEs are stable even in a physiological condition (pH 7), where the naked {RuIII2(-OH)} complex is readily transformed into its deprotonated {RuIII2(micro-O)} form, demonstrating an unusual stabilizing effects for the {RuIII2(micro-OH)} unit by the Nafion cluster environment.
authors.affiliation: Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-higashi-machi, Nara 630-8285, Japan.
authors.forename: Annamalai Senthil
authors.initials: AS
authors.lastname: Kumar
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tanase
authors.forename: Masayasu
authors.initials: M
authors.lastname: Iida
mesh_terms: D000838:Anions; D002384:Catalysis; D004563:Electrochemistry / Q000379:methods; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000838:Anions; D005465:Fluorocarbon Polymers; D007477:Ions; C504137:nitrosonium ion; D009569:Nitric Oxide; C040402:perfluorosulfonic acid; D012428:Ruthenium