Electroreduction of diazonium salts

L. M. Santos, J. Ghilane, C. Fave, P.-C. Lacaze, H. Randriamahazaka, L. M. Abrantes, and J.-C. Lacroix, Electrografting polyaniline on carbon through the electroreduction of diazonium salts and the electrochemical polymerization of aniline, J. Phys. Chem. C, 112, 16103-16109 (2008). 

The electroreduction of diazonium salts, described in Figure 9.2 and extensively used to graft hydrogenases onto electrodes, also proved to be an efficient alternative method to form covalent linkages between a model compound and a carbon electrode [27]. This was applied by Darensbourg and coworkers... 

Fontaine, O., J. Ghilane, P. Martin, J.-C. Lacroix, and H. Randriamahazaka. Ionic liquid viscosity effects on the functionalization of electrode material through the electroreduction of diazonium salts. Langmuir 26, 2010 18542-18549. 

Fig. 3 Covalent attachment of functionalized aryl molecules to the surface of carbon electrodes by the electroreduction of phenyl diazonium salts in nonaqueous medium.

Owing to the easy electroreduction of such species, the electrografting of aryl diazonium salts has been quite easily achieved in aqueous media [15]. For this purpose, the pH of the solution has to be kept below 2 (e.g., by the addition of H2SO4) in order to avoid degradation of the diazonium salt by its reaction with water. This advantage is of importance for both ecologic and economic impacts of the method. 

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