Highly trans-1,4 selective (co-)polymerization of butadiene and isoprene with quinolyl anilido rare earth metal bis(alkyl) precursors

摘要

The N-R-quinolinyl-8-amino ligands HL~(1-3) (R = 2,6- ~iPr_2C_6H_3 (HL~1), 2,6-Et_2C_6H_3 (HL~2), 2,6-Me _2C_6H_3 (HL~3)) have been prepared, which reacted readily with one equiv. of rare earth metal tris(alkyl)s to afford the corresponding bis(alkyl) complexes L~1Y(CH_2SiMe _3)_2(THF) (1) and L~(1-3)Lu(CH_2SiMe _3)_2(THF) (2-4) via alkane elimination. Contrastingly, treatment of the in situ generated neodymium tri(alkyl)s with HL~1 afforded a mono(alkyl) neodymium complex (5). Complexes 1, 2 and 5 in combination with aluminium alkyls and organoborates established homogenous ternary systems that exhibited versatile catalytic activities and trans-1,4 selectivities for the polymerization of butadiene, depending on the types of aluminium alkyl, organoborate and rare earth metal used. Furthermore, the trans-1,4 selective copolymerization of butadiene and isoprene was achieved by using the ternary system of 1/AlMe_3/[Ph_3C][B(C _6F_5)_4]. Both the kinetics of copolymerization and the thermal behavior of the copolymers were investigated.