Allyl complexes of the rare earth metals, and their application in homogeneous catalysis

This thesis aims at the synthesis of new organometallic compounds of the early lanthanides. Since there is no systematic study using tris(allyl) complexes as an alternative to the thermally instable tris(trimethylsilylmethyl) precursors for the synthesis of early rare earth metal complexes, this project intends to lead to a thorough understanding of this type of compounds. Various ligands and early rare earth metals were tested in their ability to form stable rare earth allyl complexes. The allyl ligand binds to rare earth metals in an 3-fashion, but in solution fluxional behavior can occur, opening up a vacant coordination site that can be occupied by substrate molecules. Factors influencing the fluxional behavior of the allyl ligands as well as electronic properties of the complexes are investigated. This work shows that tris(allyl) complexes are useful precursors for the synthesis of a large range of rare earth metal complexes. Allyl compounds of early rare earth metals are thermally more stable than their trimethylsilylmethyl analogues. In addition to known applications such as the polymerization of 1,4-butadiene, allyl complexes are used as precatalysts for the hydrosilylation of C=C and C=O double bonds, in which selectivities are tuned both by the metal and the ligand.