On the mechanism of the Kharash reaction catalyzed by Fe(CO)5

Fe(CO)₅ is sufficiently stable at 80 °C in benzene solution and its thermal decomposition is not accelerated in the presence of phenyl cinnamate or/and DMF. The decomposition is accelerated by CCl₃Br (drastically) and by CCl₄ (to a lesser extent). DMF accelerates the reaction of Fe(CO)₅ with CCl₄. The (FeCl(DMF)₅]²⁺[Cl₃FeOFeCl₃]^2– complex has been isolated as a product; its composition and structure have been determined by X-ray analysis. The obtained data indicate the absence of coordination of DMF or/and an olefin with Fe⁰ species at the stage preceding oxidation. The mechanisms of the generation of CCl₃ radicals in thermal and photochemical Kharash reactions in the presence of Fe(CO)₅ are basically different. The probable pathways of the effect of DMF on the rate of the oxidative decomposition of Fe(CO)₅ are discussed.For Part 2, see Ref. 1.Translated from IzvestiyaAkademii Nauk. Seriya Khimicheskaya, No. 4, pp. 916–919, April, 1996.