Ab initio theoretical study of the reactivity as bases or nucleophiles of potassium and lithium methides

The metal-hydrogen exchange reaction of LiMe KOMe 1:1 complex with CH4 is first examined, and its reactivity is found to be quite similar to that displayed by LiMe alone. On this basis, other possible aggregations are studied. The 1:3 complex, in which Me- and Li+ are kept ca. 3.5 � apart by three K+ ions and three negative oxygen atoms, respectively, is particular interesting. Its formation is computed to be easier than that of 3:1 tetramer. On the basis of its structural and electronic features, this complex can be considered a good candidate as a reactive metalating species.