Solution and solid phase electrochemical behaviour of [Os(bpy)3]3[P2W18O62]

Fay, Nigel and Dempsey, Eithne and McCormac, Timothy (2005) Solution and solid phase electrochemical behaviour of [Os(bpy)3]3[P2W18O62]. Electrochimica Acta , 51 (2). pp. 281-288. ISSN 0013-4686

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[Os(bpy)3]3[P2W18O62] has been synthesised and characterised by elemental analysis,spectroscopic (UV/Vis, IR spectroscopy) and electrochemical techniques. In 0.1M Bu4NPF6DMSO the complex shows a series of redox couples associated with the Os3+/2+ and bipyridine ligands of the cationic [Os(bpy)3]2+ moiety and the tungsten-oxo framework of the associated Dawson parent heteropolyanion, [P2W18O62]6-. At this electrolyte concentration the Os3+ redox form of the complex was seen to adsorb onto the electrode surface. When the electrolyte concentration is lowered to 0.01M Bu4NPF6 in addition to the Os3+/2+ redox couple,the redox process associated with the [P2W18O62]8-/7- couple also exhibited properties indicating surface based processes were present. Electroactive films of the complex were formed on carbon macroelectrodes by the redox switching of the transition metal within the complex. Voltammetric investigations into the film’s behaviour in a range of buffer solutions(pH 2.0, 4.5 and 7.0) were performed. The films were found to possess better stability in acidic pH and the same pH dependence for the tungsten-oxo framework of the heteropolyanions as in solution. Solid state electrochemical measurements on mechanically attached microparticles of the complex were performed, with the effect of both the nature and concentration of the aqueous electrolyte on this behaviour being investigated. Upon redox switching between the Os2+/3+ redox states there is an associated insertion/expulsion of anions from/to the solution phase. Scanning electron micrographs of these solid state films were attained before and after redox cycling.

Item Type: Article
Uncontrolled Keywords: Heteropolyanion; Bipyridine; Adsorption; Solid state
Subjects: Science > Chemistry
Research Centres: Electrochemistry Research Group
Depositing User: Nicola Hanlon
Date Deposited: 10 Mar 2011 12:53
Last Modified: 11 Nov 2014 16:09

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