title: Some evidence for the formation of an azo bond during the electroreduction of diazonium salts on Au substrates.
abstract: Molecular films obtained by electrochemical reduction of diazoniuim tetrafluoroborate salts [4-carboxybenzene (PhCOOH) and 4-amino-(2,3,5,6-tetrafluoro)-carboxybenzene (PhF(4)COOH)] on Au substrates and post-functionalization with an osmium pyridil-bipyridine complex are studied by a combination of X-ray photoelectron (XPS) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS). The spectroscopic evidence suggests the formation of N=N bonds tethering the complexes to Au. The surface coverage of the azo-bonded osmium complexes strongly depends on the electrode potential. The resulting tethered osmium redox centres were characterized by cyclic voltammetry and impedance spectroscopy. Similar electron transfer-rate constants were measured for both fluorinated and non fluorinated benzene-linked Os complexes.
authors.affiliation: Departmento de Quìmica Inorgánica, Analítica y Química Física, INQUIMAE. Facultad de Ciencias Exactas y Naturales, Pabellón 2, Ciudad Universitaria. AR-1428. Buenos Aires, Argentina.
authors.forename: Alejandra M
authors.initials: AM
authors.lastname: Ricci
authors.forename: Lucila P
authors.initials: LP
authors.lastname: Méndez De Leo
authors.forename: Federico J
authors.initials: FJ
authors.lastname: Williams
authors.forename: Ernesto J
authors.initials: EJ
authors.lastname: Calvo