Synthesis and Characterization of Organo-Rare-Earth Metal Monoalkyl Complexes Supported by Carbon 蟽-Bonded Indolyl Ligands: High Specific Isoprene 1,4-Cis Polymerization Catalysts

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• 作者：Liping Guo ; Xiancui Zhu ; Guangchao Zhang ; Yun Wei ; Lixin Ning ; Shuangliu Zhou ; Zhijun Feng ; Shaowu Wang ; Xiaolong Mu ; Jun Chen ; Yuzhe Jiang
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：June 15, 2015
• 年：2015
• 卷：54
• 期：12
• 页码：5725-5731
• 全文大小：377K
• ISSN：1520-510X

文摘

A series of N-protected 3-imino-functionalized indolyl ligands 1-R-3-(R鈥睳鈺怌H)C₈H₅N [R = Bn, R鈥?= 2,6-ⁱPr₂C₆H₃ (HL¹); R = CH₃, R鈥?= 2,6-ⁱPr₂C₆H₃ (HL²); R = Bn, R鈥?= ^tBu (HL³)] and 1-CH₃-2-(2,6-ⁱPr₂C₆H₃N鈺怌H)C₈H₅N (HL⁴) was prepared via reactions of N-protected indolyl aldehydes with corresponding amines. The C鈥揌 蟽-bond metathesis followed by alkane elimination reactions between RE(CH₂SiMe₃)₃(thf)₂ and HL¹鈥揌L³ afforded the carbon 蟽-bonded indolyl-ligated rare-earth metal monoalkyl complexes. Reactions of RE(CH₂SiMe₃)₃(thf)₂ with 2 equiv of HL¹ or HL² gave the carbon 蟽-bonded indolyl-ligated rare-earth metal monoalkyl complexes L¹₂RECH₂SiMe₃ (RE = Y(1), Er(2), Dy(3)) and L²₂RECH₂SiMe₃ (RE = Y(5), Er(6), Dy(7), Yb(8)), while reaction of Yb(CH₂SiMe₃)₃(thf)₂ with 2 equiv of HL¹ afforded the ytterbium dialkyl complex L¹Yb(CH₂SiMe₃)₂(thf)₂ (4). Reactions of RE(CH₂SiMe₃)₃(thf)₂ with HL³ gave the tris(heteroaryl) rare-earth metal complexes L³₃RE (RE = Y(9), Er(10)). In the presence of cocatalysts, the rare-earth metal monoalkyl complexes initiated isoprene polymerization with a high activity (90% conversion of 1000 equiv of isoprene in 25 min) producing polymers with high regio- and stereoselectivity (1,4-cis polymers up to 99%).