Synthesis and Reactions of Manganese(II) Dialkyl Complexes Containing Monodentate and Bidentate Nitrogen Ligands

Abstract

In this paper we describe the synthesis of Mn(II) dialkyl compounds and their adducts with THF and pyridine. These compounds are useful precursors for the preparation of Mn complexes relevant to catalysis, such as dialkylmanganese(II) derivatives containing chelating nitrogen ligands. In contrast with previously known manganese(II) dialkyls, dibenzylmanganese can not be prepared from MnCl2 and benzylmanganese chloride due to the formation of insoluble mixed manganese−magnesium compounds. Homoleptic manganese(II) dialkyls are highly sensitive and often quite insoluble owing to their polymeric structure. However, adducts of type MnR2L or MnR2L2 (L = THF, pyridine) are soluble in hydrocarbon solvents and more readily isolated and stored than the homoleptic alkyls compounds. Manganese dialkyls as well as their THF or pyridine adducts react instantly with 2,2′-bipyridyl to afford the corresponding MnR2(bipy) complexes. Thus, the stabilized dialkylmanganese(II) THF or Py adducts represent a practical alternativ...