Introduction - Why Couple Techniques

Homogeneous Spectroelectrochemical Probes In Situ Electron Spin Resonance (ESR) [7-10] 

Molecules with unpaired electrons may be detected by microwave spectroscopy in the presence of a magnetic field. This technique is of considerable importance for the detection of radical reaction intermediates produced during electrolysis. 

The light absorption of reaction intermediates generated at the electrode surface can be monitored in transmission or in reflection mode and this allows sensitive detection and/or quantitative kinetic studies. 

Compared to the absorption of light in the visible wavelength range, luminescence is a much more sensitive technique due to the absence of background radiation. Even single photons may be counted and analysed in chemiluminescence processes [15]. 

NMR is very widely used and a powerful tool for structure determination. Although commonly used for diamagnetic compounds, it may also be applied to paramagnetic materials [17]. 

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