EPR spectroelectrochemistry

To learn that the most common problems experienced with in situ EPR spectroelectrochemistry work result from employing a solvent that itself absorbs microwave radiation, and from using polymers which contain radical species. 

In situ EPR spectroelectrochemistry monitors paramagnetic species, usually radicals in solution. The chemical stability of such species can be readily determined by this technique. It was seen that the most conunon problems encountered with in situ electrochemical EPR work emanate from the use of absorbing solvents and polymers containing paramagnetic impurities. 

Figure 7.1 Schematic representation of the in-situ, variable-temperature flat cell for EPR spectroelectrochemistry.

UV-vis methods are often combined with other techniques. For example, combined UV-vis and EPR spectroelectrochemistry was used in the study of anthraquinone reduction. But the EPR spectro-electrochemical cell design is demanding to implement successfully and the presence of the metal electrodes within the cell reduces sensitivity considerably (see later). 

P. Berdyezko, W. Domagala, A. Czardybon, and M. Lapkowski. 2009. Long alkyl chain bearing derivatives of poly(3,4-ethylenedioxythiophene) studied by in situ EPR spectroelectrochemistry. Synth Met 159(21-22) 2240-2244. 

Os°(bpy)(CO)2] polymer has been characterized by IR, UV-Vis and EPR spectroelectrochemistry. The polymer species is an electron-rich electrocatalyst for CO2 reduction and its fair solubility in polar organic solvents is important for potential use. 

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