Spectroelectrochemical determination of the electron consumption.

Abstract 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.