Reversible Formation Of A Cerium-Bound Terminal Hydride: Ce(C5me4sime3)(2)(H)(Thf)

The use of the bulky cyclopentadienyl ligand Cp' (Cp' = C5Me4SiMe3) to stabilize cerium hydrides has resulted in the preparation of two novel tuck-in complexes with C-H activated SiMe3 groups. Subsequent reaction of these with H-2 in thf gives a lanthanide terminal hydride species Ce(Cp')(2)(H)(thf) which reversibly regenerates the tuck-in complex under sustained vacuum. This compound is only the second structurally characterized terminal cerium hydride. This new hydride is a catalyst in H/D exchange reactions between with both sp(3)-CH and sp(2)-CH bonds, and for the hydrogenation of unsaturated alkene bonds.