Synthesis, characterization and reactivity of rare-earth metal amide complexes supported by pyrrolyl-substituted cyclopentadienyl ligand

Abstract

Absaact Amine elimination between rare-earth metal tris(amide) complexes Ln [N(SiHMe2)2]3 (THF)x and 1 equiv. of pyrrolyl-substituted cyclopentadienyl ligand C4H4NSiMe2C5Me4H was investigated. Reaction of C4H4NSiMe2C5Me4H and Ln [N(SiHMe2)2]3 (THF)x with small metals afforded the half-sandwich rare-earth metal bis(silylamide) complexes (C4H4NSiMe2C5Me4)Ln [N(SiHMe2)2]2 (Ln = Sc (1), Y (2)), while the same reaction using La [N(SiHMe2)2]3 (THF)2 isolated lanthanum mono-silylamide complex [C5Me4SiMe2N(SiHMe2)2]La [N(SiHMe2)2](C4H4N) (3). These complexes were characterized by elemental analysis and NMR spectroscopy. 1 and 3 were structurally authenticated by single crystal X-ray diffraction. The ternary catalyst systems of 1 or 2/AliBu3/[Ph3C][B(C6F5)4] showed activity towards styrene polymerization to give pure syndio-tactic polystyrenes (rrrr > 99%).