One Ligand Fits All: Cationic Mono(amidinate) Alkyl Catalysts over the Full Size Range of the Group 3 and Lanthanide Metals

Using a sterically demanding amidinate ancillary ligand and an in situ alkylation procedure, neutral mono(amidinate) dialkyl and cationic mono(amidinate) monoalkyl complexes were prepared for metals spanning the full size range of the group 3 and lanthanide metals. The activity of the cationic monoalkyls in catalytic ethene polymerization was found to vary by over 2 orders of magnitude depending on the metal ionic radius, the intermediate metal sizes being found to be the most effective.