Synthesis and characterization of constrained-geometry half-sandwich sila- and germacarboranes derived from a trianionic C(cage)-appended alkyloxo-C2B9-carborane ligand

The reaction of the [nido-7-(OCH2)-8-Me-7,8-C2B9H9]3− trianion with anhydrous MeMCl3 (M=Si, Ge) in 1:1 molar ratio in dry toluene, followed by re-crystallization from a solution of toluene/heptane, resulted in the formation of the corresponding novel half-sandwich constrained-geometry group 14 metallacarboranes, closo-1-M(Me)-2-(1-η1(σ)-OCH2)-3-Me-η5-2,3-C2B9H9 [M=Si (3), Ge (4)] in 48% and 56% yields, respectively.