Electrochemical behavior of [{(arene)ruci2}2] complexes, determination of kinetic parameters using the rotating ring-disk electrode

• Verónica Arancibia ^[1] ; Mauricio Valderrama ^[1] ; Raúl Contreras ^[1] ; Patricio Muñoz ^[1]
  1. [1] Pontificia Universidad Católica de Chile

     Pontificia Universidad Católica de Chile

     Santiago, Chile

     
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 48, Nº. 4, 2003, págs. 95-100
• Idioma: inglés
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• Resumen

  • The electrochemical behavior of binuclear ruthenium(II) complexes of the type [{(arene)RuCl2}2] where arene = benzene (1), toluene (2), p-cymene (3) and hexamethylbenzene, (HMB) (4), have been studied by cyclic voltammetry, coulometry and voltammetry with rotating disk and ring-disk electrodes. These compounds undergo electrochemical quasi-reversible reduction in dimethylsulphoxide (DMSO) and acetonitrile (MeCN). The ruthenium(I) species formed react in a very fast chemical reaction (EC mechanisms), although the rate constants of electrochemical and chemical processes are different for the arenes studied. Conditional rate constants (k) and charge transfer coefficients (a ) for the cathodic reactions were determined by rotating disk techniques, and the kinetic collection efficiency (Nk) was determined with a rotating ring-disk electrode. On the other hand, the binuclear complexes 1 and 2 are quasi-reversibly oxidized in MeCN solution in two electron steps yielding binuclear Ru(III) species, while complex 3 is partially oxidized to give a mixture of products, and complex 4 generates a very unstable species, which chemically returns to the starting reduced complex