Methane as the product of reaction of methyl-coenzyme-M with monovalent nickel complexes in aqueous solutions. A model for the in vivo activity of cofactor F₄₃₀

Solutions containing the monovalent macrocyclic nickel complexes 1 and 2 were prepared by irradiating with ionizing radiation He saturated solutions containing the divalent complexes and 0.01 M HCO₂Na. Deaerated solutions containing methyl-coenzyme- M (MeCoM) were then injected into the vials containing the monovalent complexes. Vague traces of methane were detected at pH 7.4 while at pH 9.4 the yield of methane is over 10%. Blank experiments point out that MeCoM scavenges methyl free radicals via a mechanism which does not produce methane as the major product. A mechanism for the formation of methane in these reactions is proposed.