High tacticity control in organolanthanide polymerization catalysis: formation of isotactic poly(alpha-alkenes) with a chiral C-3-symmetric thulium complex

The thulium complexes [Tm(Pr-i- trisox)(CH2SiMe2R)(3)] (R = Me 1a, Ph 1b) were synthesized from the thulium trialkyl precursors [Tm(CH2SiMe2R)(3)(thf)(2)]; reaction of 1a with two equivalents of [Ph3C][B(C6F5)(4)] gave a cationic complex 1c, which was found to polymerize 1-hexene, 1-heptene and 1-octene to give the corresponding polyolefins with moderate to good activities and with minimum isotacticity of 90%, 83% and 95%, respectively.