Borohydride complexes of rare earths, and their applications in various organic transformations

Borohydride complexes of the rare earths have attracted increasing interest during the last decade. This review aims to cover recent results over this period with respect to the preparation, characterization, structure, and applications in organic chemistry of this family of compounds, including inorganic and organometallic complexes. Special emphasis is made on their use for polymerization catalysis.

Research highlights▶ The trisborohydrides are a good alternative for the synthesis of organolanthanides. ▶ The borohydride ligand brings solubility and can be analyzed by NMR. ▶ Original Borohydrido derivatives can be prepared when halide analogs are not isolable. ▶ Borohydrides of the rare earths are a valuable option for polymerization catalysis. ▶ They can initiate reactions towards polar monomers by themselves. ▶ They are highly efficient as pre-catalysts towards non polar monomers.