Mono(η⁵-Pentamethylcyclopentadienyl) Complexes of Osmium

The chemistry of transition metal mono(cyclopentadienyl) molecules of the type (η-C5R5)MXn, where X is a halide ligand, has been widely explored. Such complexes can serve as catalysts or catalyst precursors for a wide variety of organic reactions ranging from the Ziegler-Natta polymerization of olefins to the hydrogenation of unsaturated hydrocarbons. These "half-sandwich" molecules are also useful starting materials for the synthesis of other cyclopentadienyl-containing species: they offer unparalleled opportunities to synthesize a wide variety of compounds that otherwise would be unobtainable. This chapter explains the procedures and properties for bromoosmic acid, bis tetrabromodiosmium(iii), and bromoosmium(ii).