Synthesis and structures of adamantyl-substituted constrained geometry cyclopentadienyl–phenoxytitanium complexes and their catalytic properties for olefin polymerization

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• 作者：Jincai Li^a ; Wei Gao^a ; Qiaolin Wu^a ; Hongchun Li^a ; Ying Mu ; ^a ; ^{ymu@jlu.edu.cn"" rel=""nofollow}
• 关键词：Ethylene polymerization ; Olefin polymerization ; Metallocene ; Titanium complex
• 刊名：Journal of Organometallic Chemistry
• 出版年：2011
• 出版时间：1 July 2011
• 年：2011
• 卷：696
• 期：13
• 页码：2499-2506
• 全文大小：459 K

文摘

A number of new constrained geometry titanium complexes, [η⁵: η¹-2-C₅Me₄-4-R-6-Ad-C₆H₂O]TiCl₂ [Ad = adamantyl, R = Me (8), ^tBu (9)] and [η⁵: η¹-C₅H₂Ph₂-4-^tBu-6-Ad-C₆H₂O]TiCl₂ (10), were synthesized from reactions of TiCl₄ either directly with corresponding free ligands, 2-C₅Me₄H-4-R-6-Ad-C₆H₂OH [R = Me (5), ^tBu (6)], or with the dilithium salt of the free ligand 2-C₅H₃Ph₂-4-^tBu-6-Ad-C₆H₂OH (7). These new titanium complexes were fully characterized by ¹H and ¹³C NMR spectroscopy and elemental analyses, and the molecular structures of 8 and 9 were determined by single-crystal X-ray crystallography. Upon activation with AlⁱBu₃ and Ph₃CB(C₆F₅)₄ (TIBA/B), these complexes exhibit high catalytic activity for 5-ethylidene-2-norbornene (ENB) polymerization as well as ethylene/1-hexene and ethylene/ENB copolymerization with good tacticity-control ability for the ENB polymerization and high comonomer incorporation ability for the copolymerization reactions. It was found that the bulky adamantyl substituent at the ortho position of the phenoxy group in the ligands of these complexes apparently influences the molecular weight and the microstructure of the resultant polymers.