Two-Dimensional Correlation Analysis of Spectroelectrochemical Data for p-Benzoquinone Reduction in Acetonitrile

Two-dimensional (2D) spectral correlation analysis has been employed to interpret the complex spectroelectrochemical data obtained from an electrochemical system undergoing following reactions after electron transfer. The system used was electrochemical reduction of p-benzoquinone (p-BQ) in acetonitrile, which produces anion radicals and dianions at its first and second reduction potentials. The dianions undergo a fast comproporationation reaction with neutral p-BQ molecules to produce anion radicals back, complicating the spectral analysis. Upon application of 2D correlation analysis in conjunction with the self-modeling curve resolution technique, we were able not only to resolve the spectra and determine the sequence of spectral emergence but also to extract the individual spectra. The techniques offer a very powerful tool for interpreting highly convoluted spectra obtained from a system where a series of chemical reactions occur following the electron transfer at the electrode/electrolyte interface.