Norbornene polymerization and copolymerization with 1-alkenes by neutral palladium complexes bearing aryloxide imidazolin-2-imine ligand

TY - JOUR

T1 - Norbornene polymerization and copolymerization with 1-alkenes by neutral palladium complexes bearing aryloxide imidazolin-2-imine ligand

AU - Li, Mingyuan

AU - Zhang, Hu

AU - Cai, Zhengguo

AU - Eisen, Moris S.

N1 - Publisher Copyright: © 2019 The Royal Society of Chemistry.

PY - 2019/6/7

Y1 - 2019/6/7

N2 - A series of novel aryloxide imidazolin-2-imine bidentate neutral Pd(ii) complexes with different substituents on the imidazolin-2-imine ligand were synthesized and characterized. In the single crystal X-ray diffraction analysis, the complexes Pd1 and Pd2 adopted almost square-planar geometries, while Pd3 bearing the bulkier 2,6-bis(diphenylmethyl)-4-methylphenyl substituent was obtained as the allyl adducted base-free η3 coordination mode. In the presence of very low EtAlCl2 loadings (100 equiv.), these Pd(ii) complexes exhibited high activity (∼106 g mol-1 h-1) and good thermal stability (up to 100 °C) toward the addition polymerization of norbornene. Most importantly, these Pd(ii) catalysts were able to promote the copolymerization of norbornene with 1-dodecene and 1-octadecene with high activity (>105 g mol-1 h-1) to yield high-molecular-weight (Mn up to 5.59 × 104 g mol-1) copolymers. The 1-alkene incorporation of resulting copolymers was modulated in a wide range (5.1-15.3%) by changing the comonomer feed ratio, accompanied by the control of the glass transition temperature (Tg = 231.6-309.6 °C). These complexes are rare examples of neutral Pd(ii) complexes toward the efficient synthesis of norbornene-based cyclic olefin copolymers (COCs).

AB - A series of novel aryloxide imidazolin-2-imine bidentate neutral Pd(ii) complexes with different substituents on the imidazolin-2-imine ligand were synthesized and characterized. In the single crystal X-ray diffraction analysis, the complexes Pd1 and Pd2 adopted almost square-planar geometries, while Pd3 bearing the bulkier 2,6-bis(diphenylmethyl)-4-methylphenyl substituent was obtained as the allyl adducted base-free η3 coordination mode. In the presence of very low EtAlCl2 loadings (100 equiv.), these Pd(ii) complexes exhibited high activity (∼106 g mol-1 h-1) and good thermal stability (up to 100 °C) toward the addition polymerization of norbornene. Most importantly, these Pd(ii) catalysts were able to promote the copolymerization of norbornene with 1-dodecene and 1-octadecene with high activity (>105 g mol-1 h-1) to yield high-molecular-weight (Mn up to 5.59 × 104 g mol-1) copolymers. The 1-alkene incorporation of resulting copolymers was modulated in a wide range (5.1-15.3%) by changing the comonomer feed ratio, accompanied by the control of the glass transition temperature (Tg = 231.6-309.6 °C). These complexes are rare examples of neutral Pd(ii) complexes toward the efficient synthesis of norbornene-based cyclic olefin copolymers (COCs).

UR - http://www.scopus.com/inward/record.url?scp=85066890394&partnerID=8YFLogxK

U2 - 10.1039/c9py00176j

DO - 10.1039/c9py00176j

M3 - 文章

AN - SCOPUS:85066890394

SN - 1759-9954

VL - 10

SP - 2741

EP - 2748

JO - Polymer Chemistry

JF - Polymer Chemistry

IS - 21

ER -