Metallocene Coordination to Neutral Alkaline Earth Metal Complexes.

The geometrically constrained, Lewis acidic magnesium diamide complex, [Mg(NON)] (NON = 4,5-bis(2,4,6-tricyclohexylanilido)-2,7-diethyl-9,9-dimethyl-xanthene), forms complexes with a series of metallocenes, [Mg(NON)(η-CpM)] (M = Mn, Fe, Co, or Ni), in which one cyclopentadienyl ring of the metallocene is η-coordinated to the magnesium center. Treating the heavier group 2 metal amide complexes, [M(NON){N(H)(SiMe)}] (M = Ca, Sr or Ba) with ferrocene yields complexes [M(NON)(η-CpFe)] in which one cyclopentadienyl ring of ferrocene is η-coordinated to the group 2 metal center. Computational studies on the metallocene complexes reveal that the metallocene-group 2 metal interactions are largely electrostatic in nature.