The reactions of transition metal chelates with organometallic compounds and their paramagnetic products. V—New possibilities in the generation of anion radicals by reactions of Grignard reagents and lithium alkyls in the presence of transition metal ions

Abstract

Abstract In the reactions of Grignard reagents and n ‐butyllithium the presence of transition metals and complexing solvents facilitates the formation of anion radicals. High radical concentrations, observable for some days at laboratory temperature, and very well resolved e.s.r. spectra of the following structural types have been obtained using a relatively simple procedure: aromatic hydrocarbons, heteroaromatics, aldehydes, ketones, α‐diketones, enolates of β‐diketones, quinones, sulphones, sulphoxides, nitro‐, nitroso‐ and azo‐benzenes, cyano compounds and phosphine oxides. It is suggested that the transition metals, according to the type of reactants and the experimental conditions, mediate the transfer of one electron to the substrate in many reactions and stabilize the intermediate products as anion radicals. The variation of solvents and organometallic compounds modifies the reduction power of such systems and leads to the radical products in a different reduction state. The procedure described is advantageously employable in the generation of anion radicals, and the effect of transition metals which has been found may widen the scope of this phenomenon to many different applications.