Amido-trihydroquinoline ligated rare-earth metal complexes for polymerization of isoprene

Amido-trihydroquinoline ligated rare-earth metal complexes have been synthesized, and in combination with a borate, all these complexes (except 2-Sc) showed moderate catalytic activities for isoprene polymerization to generate 1,4-enriched polyisoprene. In particular, the 2-Y-based catalytic system promoted the isoprene polymerization in a well-controlled manner. The alkylaluminium (AIR(3), R = Me, Et, 'Bu) exerted a different influence on the polymerization, and AIMe(3) enhanced not only the catalytic reactivity but also the 1,4-selectivity significantly. Considering the influence of the polar sequence on improving the surface property of the non-polar polymer, we further successfully realized the polymerization of c-caprolactone and its Nock copolymerization with isoprene by utilizing the active yttrium-polyisoprene species as the marcointiator. The fact that the higher content of the hydrophilic PCL sequence in the copolymer gave a lower WAC, proved the tunable modification of the copolymer's surface hydrophilicity.

Automated summary

Amido-trihydroquinoline ligated rare-earth metal complexes have been synthesized and showed moderate catalytic activities for isoprene polymerization. The 2-Y-based catalytic system exhibited excellent control over the polymerization. The alkylaluminium exerted varying influence on the polymerization, and AIMe(3) significantly enhanced the reactivity and 1,4-selectivity. The active yttrium-polyisoprene species were successfully utilized for the polymerization of caprolactone and its copolymerization with isoprene, demonstrating the tunable modification of the copolymer's surface hydrophilicity, with higher content of hydrophilic PCL sequence resulting in lower WAC.