Bromonitriles reduction. The effect of the electrode material on the structure of the reaction intermediates and the electrolysis products

✍ Scribed by Italo Carelli; Antonella Curulli; Achille Inesi; Errico Zeuli

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 503 KB
• Volume: 30
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(85)80154-7

✦ Synopsis

The electrochemical reduction has been studied on BrCRZ(CH2).CN bromonitriles [(I) R = CH,, n = 0; (II) R = H, n = 1; (III) R = H, n = 2; (IV) R = H, n = 31 in N,N'-dimethylformamide solution with Et,NClO, as supporting electrolyte, at the Hg electrode or the vitreous carbon one. With both electrodes all the investigated bromonitriles undergo a one-electron transfer reduction, which shifts towards a two-electron one in the presence of protonating agents. The reduction potentials, the nature, and the yield of products depend on the electrode material. The reduction of (I) and (II) @1/z > Es) on Hg pool yields debrominated nitriles, dimeric, and polymeric compounds. In contrast, the reduction at the vitreous carbon electrode yields debrominated and unsaturated nitriles, but does not yield dimeric and polymeric material. Three-and four-membered ring nitriles have been obtained in comparable yields upon reduction of (III) and (Iv) (EIIP = E F ) at both electrodes. The reduction of (II) at vitreous carbon has been described as an examp e of "mixed" electron exchange occurring both directly at the electrode and indirectly in solution via (CH,=CHCN)' (homogeneous redox catalysis).