Spectroelectrochemical determination of the electron consumption

• Published in: Analytica chimica acta Vol. 697; no. 1; pp. 23 - 26
• Main Authors: KOLIVOSKA, Viliam, GAL, Miroslav, LACHMANOVA, Stěpánka, VALASEK, Michal, HROMADOVA, Magdaléna, POSPISIL, Lubomír
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04-07-2011; Elsevier
• Subjects: Analytical chemistry; Calibration; Chemistry; Consumption; Coulometers; Coulometry; Electrochemical methods; Electrochemistry - methods; Electrolysis; Electrons; Exact sciences and technology; Exchanging; Ferrous Compounds - chemistry; Mathematical analysis; Metallocenes; Molecular Weight; Number of electrons; Oligomers; Optical Phenomena; Oxidation-Reduction; Paraquat - chemistry; Spectra; Spectroelectrochemistry; Spectrometric and optical methods; Spectrum Analysis; Thin films; Water - chemistry; Number of electrons; Electrolysis; Spectroelectrochemistry; Coulometry; Reaction intermediate; Oxidation reduction; Estimation; Calibration; Method; Oligomer; Reduction; Volume; Oxidation; Ultraviolet visible spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2011.04.033

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► Measurements of UV–vis spectra as a function of charge yield rapidly and in a small volume the number of exchanged electrons. ► The determination of
n is based on the calibration procedure using the ferrocene oxidation and the methyl viologen reduction. ► This method eliminates problems of side reactions of intermediates with the parent form by using a thin layer optical cell.
Measurements of UV–vis spectra as a function of the consumed charge in an optically transparent thin layer cell (OTTLE) offer a fast, small-volume and reliable method for the determination of the number of electrons
n exchanged in the redox reaction. The determination of
n is based on the calibration procedure using the ferrocene oxidation and the methyl viologen reduction. Virtues of this method are demonstrated on the determination of
n of two oligomers of ‘extended viologens’ with multiple redox centers and correspondingly large
n. The described method eliminates problems of side reactions of reactive intermediates with the parent oxidized form, which often impede a reliable estimation of
n by the established coulometric method.