TY - JOUR
T1 - Chiral palladium(II) and nickel(II) complexes with C2-symmetrical tridentate bis(oxazoline) ligands
T2 - Synthesis, characterization, and catalytic norbornene polymerization
AU - He, Jianyun
AU - Liu, Zhanxiong
AU - Du, Gaixia
AU - Fu, Yinxia
AU - Zhang, Shaowen
AU - Li, Xiaofang
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2014/11/10
Y1 - 2014/11/10
N2 - A series of chiral palladium(II) and nickel(II) complexes bearing a C2-symmetric monoanionic tridentate bis(oxazoline) ligand, (R2-(S,S)-BOZ)M(X) (1-6: R = CH(CH3)2, M = Pd, X = OAc (1); R = CH(CH3)2, M = Pd, X = Cl (2); R = Ph, M = Pd, X = Cl (3); R = Ph, M = Ni, X = Cl (4); R = CH(CH3)2, M = Ni, X = Cl (5); R = CH(CH3)2, M = Pd, X = OTf (6)), have been synthesized and structurally characterized. The experimental results demonstrate that such chiral palladium(II) and nickel(II) complexes bearing C2-symmetric tridentate ligands in which the monoanionic group is located inside are effective for norbornene polymerization. In the presence of various cocatalysts such as MAO, MMAO, and activator/AlR3, these chiral palladium(II) complexes exhibit much higher activities of up to 4.8 × 108 g of PNB (mol of Pd)-1 h-1 for the vinylic polymerization of norbornene, affording insoluble polynorbornenes with high packing density. In contrast, the chiral nickel(II) complexes show relatively low activities of ca. 4.5 × 107 g of PNB (mol of Ni)-1 h-1 and produce both insoluble polynorbornenes and soluble high-molecular-weight polynorbornenes with moderate molecular weight distributions.
AB - A series of chiral palladium(II) and nickel(II) complexes bearing a C2-symmetric monoanionic tridentate bis(oxazoline) ligand, (R2-(S,S)-BOZ)M(X) (1-6: R = CH(CH3)2, M = Pd, X = OAc (1); R = CH(CH3)2, M = Pd, X = Cl (2); R = Ph, M = Pd, X = Cl (3); R = Ph, M = Ni, X = Cl (4); R = CH(CH3)2, M = Ni, X = Cl (5); R = CH(CH3)2, M = Pd, X = OTf (6)), have been synthesized and structurally characterized. The experimental results demonstrate that such chiral palladium(II) and nickel(II) complexes bearing C2-symmetric tridentate ligands in which the monoanionic group is located inside are effective for norbornene polymerization. In the presence of various cocatalysts such as MAO, MMAO, and activator/AlR3, these chiral palladium(II) complexes exhibit much higher activities of up to 4.8 × 108 g of PNB (mol of Pd)-1 h-1 for the vinylic polymerization of norbornene, affording insoluble polynorbornenes with high packing density. In contrast, the chiral nickel(II) complexes show relatively low activities of ca. 4.5 × 107 g of PNB (mol of Ni)-1 h-1 and produce both insoluble polynorbornenes and soluble high-molecular-weight polynorbornenes with moderate molecular weight distributions.
UR - http://www.scopus.com/inward/record.url?scp=84910011715&partnerID=8YFLogxK
U2 - 10.1021/om5007616
DO - 10.1021/om5007616
M3 - Article
AN - SCOPUS:84910011715
SN - 0276-7333
VL - 33
SP - 6103
EP - 6112
JO - Organometallics
JF - Organometallics
IS - 21
ER -