Synthesis and Novel Polymerization and Copolymerization Reactions of New Organolanthanide Complexes.

Reactions of (C5Me5) 2Sm (THF) 2 with the potassium salts of monodentate anionic ligands ER (ER=OAr, SAr, NR1R2, etc.) yielded a series of C5Me5/ER-ligated samarium (II) complexes, which were stabilized by the neutral “C5Me5K” ligand. These complexes act as a unique catalytic system which can not only polymerize styrene and ethylene, but also copolymerize them into block styrene-ethylene copolymers under the presence of both monomers. Addition of an appropriate cocatalyst such as MMAO or AlR3/ [Ph3C] [B (C6F5) 4] to the samarocene complex (C5Me5) 2Sm (THF) 2 or (C5Me5) 2Sm (μ-Me) 2AlMe2 afforded a novel catalytic system for stereospecific 1, 4-cis living polymerization of butadiene and copolymerization of butadiene with styrene. The samarium (II) bis (aryloxide) complex Sm (OAr) 2 (THF) 3 showed an extremely high activity for ring-opening polymerization of ε-caprolactone and δ-valerolactone and copolymerization of ε-caprolactone with γ-butyrolactone.