ABSTRACT
Many electrochemical reactions that produce radicals are reported in the different chapters of this book:thereductivecleavageofaliphaticoraromatichalides(Chapters24and25),theoxidative cleavageofcarboxylicacids(Chapter33),theoxidationororganometalliccompounds(Chapter 36),andthereductionandprotonationofaldehydesandketones(Chapter31).Theseradicalsare involvedinmanyreactionssuchasdimerizations(e.g.,theKolbereaction),SRN1 reactions, addition toalkenes,Pschorrreaction,andradicalcascadecyclization.Thischapterdescribesnewreactions ofsomeoftheseradicals: the reaction with surfacesrangingfromcarbonandpolymerstosemiconductorsandevenmetals(nobleorindustrialmetals).Theradicalsdescribedinthischapterare aminylradicals(byoxidationofamines),alkylandbenzylradicals(byoxidationofcarboxylates and of Grignard reagents or by reduction of alkyl halides and vinylics), aromatic radicals (by oxidationoforganomagnesiumcompounds,byreductionofdiazoniumsalts),hydroxylradicals(fromthe electro-Fentonreaction),butalsoradicalsthatarepreparedbyindirectreactionssuchas(1)alkyl radicalsobtainedbyattackofanaromaticradicalonvinylicsor(2)cyanomethylradicalresulting fromthehydrogenabstractionfromacetonitrile.Thešrstreportofthereactionofaradicalwith a metallic substrate is due to Lecayon and coworkers at the Commissariat à l’Energie Atomique in1982[1]:thinlayerswereobtainedandcharacterizeduponreductionofvinylicsonmetallic cathodes(electrografting).Inthecourseofthereactionofradicalswithsurfaces,abondisformed betweenthesurfaceandthešlm(chemisorption).Itmustbeclearlydistinguishedfromadsorption ofteninvolvedinelectrochemicalprocesses(physisorption);itishoweverlikelythatintheolder literature real grafting has been mistaken for physisorption.
