Chiral Palladium(II) and Nickel(II) Complexes with C2-Symmetrical Tridentate Bis(oxazoline) Ligands: Synthesis, Characterization, and Catalytic Norbornene Polymerization

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• 作者：Jianyun He ; Zhanxiong Liu ; Gaixia Du ; Yinxia Fu ; Shaowen Zhang ; Xiaofang Li
• 刊名：Organometallics
• 出版年：2014
• 出版时间：November 10, 2014
• 年：2014
• 卷：33
• 期：21
• 页码：6103-6112
• 全文大小：571K
• ISSN：1520-6041

文摘

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鈥?b>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 脳 10⁸ g of PNB (mol of Pd)^鈭? h^鈥? 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 脳 10⁷ g of PNB (mol of Ni)^鈭? h^鈥? and produce both insoluble polynorbornenes and soluble high-molecular-weight polynorbornenes with moderate molecular weight distributions.