Syntheses, Characterization, and Ethylene (Co-)Polymerization Screening of Amidate Half-Titanocene Dichlorides

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• 作者：Shaofeng Liu ; Wen-Hua Sun ; Yanning Zeng ; Deligeer Wang ; Wenjuan Zhang ; Yan Li
• 刊名：Organometallics
• 出版年：2010
• 出版时间：June 14, 2010
• 年：2010
• 卷：29
• 期：11
• 页码：2459-2464
• 全文大小：760K
• 年卷期：v.29,no.11(June 14, 2010)
• ISSN：1520-6041

文摘

A series of amidate half-titanocene dichlorides, Cp′TiLCl₂ [Cp′ = Cp (as η⁵-C₅H₅) or Cp* (as η⁵-C₅Me₅), L = N-(2-methylquinolin-8-yl)-p-R-benzamides; C1: Cp′ = Cp, R = OMe; C2: Cp′ = Cp, R = Me; C3: Cp′ = Cp, R = H; C4: Cp′ = Cp, R = F; C5: Cp′ = Cp, R = Cl; C6: Cp′ = Cp*, R = OMe; C7: Cp′ = Cp*, R = Me], have been synthesized by the stoichiometric reaction of Cp′TiCl₃ with the corresponding potassium amidates. All complexes are fully characterized by elemental and NMR analyses. The molecular structures of complexes C2 and C4 are confirmed by single-crystal X-ray diffraction, and the amidate moieties coordinate the titanium center by imino and alkoxide groups. The systems C1−C7/MAO show much higher activities toward ethylene polymerization than CpTiCl₃/MAO or Cp*TiCl₃/MAO systems. The procatalysts (C6 and C7) bearing a Cp* ligand exhibit higher activities than their analogues (C1−C5) containing a Cp ligand, while the amidate ligands containing electron-donating groups positively affect the catalytic behavior. Both increasing the ratio of MAO to titanium and reducing reaction temperature enhance the productivities; however, the molecular weights of the resultant polymers decrease with higher activities. Moreover, the C6/MAO system performs with high activity in the copolymerization of ethylene and 1-hexene or 1-octene.