Metal-to-Ligand Alkyl Migration on Rare Earth Metal Complexes: Synthesis, Characterization and Catalytic Activity in the Isoprene Polymerization.

Neutral LnIII-dialkyl (YIII, LuIII, ErIII, YbIII) complexes stabilized by tridentate ?N-,N,N? monoanionic thiazole or benzothiazole amidopyridinate ligands have been synthetized and completely characterized. Notably, a progressive rearrangement of the coordination sphere takes place on the benzothiazole containing systems through an unprecedented metal-to-ligand alkyl migration and subsequent thiazole ring-opening; the generation of monoalkyl aryl thiolate organolanthanide species stabilized by a tetradentate ?N-,N,N,S-? dianionic ligands will be discussed on both an experimental and theoretical ground (Scheme 1).1 Selected complexes from this series, in their cationic form, have shown remarkable diene polymerization activities; their catalytic performance in the isoprene (IP) polymerization will be discussed.