Catalytic Reduction of Unsaturated Halides by Ni(II) Complexes

Abstract

Radical cyclisation is rapidly becoming an important method for the formation of cyclic systems. Hence, some electrochemical results obtained in the study of electroreductive intramolecular cyclisation of different types of unsaturated halides using nickel(II) complexes as mediators, are presented.

Electroreductive Remediation of Halogenated Environmental Pollutants

“…Of particular interest in our laboratory is electrogenerated nickel­(I) salen ( 3 ), which was introduced earlier in this review. This species has been used as a catalyst for the reductive intramolecular cyclizations of a variety of olefinic and acetylenic halides, − as well as for the reduction of α,ω-dihaloalkanes . In the presence of carbon dioxide, nickel­(I) salen was shown to promote the reductive electrocarboxylation of benzylic halides and arylethyl chlorides .…”

Comparison of chemical interactions with Li+ and catalytic reactivity of electrochemically generated [FeICl(L)]2− and [CoI(L)]− complexes (L = salen or salophen)

“…[16][17][18][19][20][21][22][23][24] Electrochemical studies on metal-salen complexes [25][26][27][28][29][30][31] have shown that [Co II (salen)] and [Ni II (salen)] exhibit reversible redox processes encompassing the metal III to I redox levels. Importantly, electrogenerated [Co I (salen)] − and [Ni I (salen)] − have been shown to catalyze the dehalogenation of halo-alkyl organic compounds such as benzyl chloride and cinnamyl chloride, [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] although they have a smaller catalytic effect on the dehalogenation of halo-aryl derivatives. [48][49][50] Alternatives to cobalt and nickel derivatives with higher catalytic activities than [Co II (salen)] and [Ni II (salen)] are of interest since they can be used for dehalogenation of halo-organic compounds, which are toxic and can damage the environment.…”