Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors

doi:10.1021/ma702505n

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	Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors
	Wang, Baoli 1,2; Cui, Dongmei 1; Lv, Kui 1,2
刊名	MACROMOLECULES
	2008-03-25
卷号	41 期号:6 页码:1983-1988
ISSN号	0024-9297
DOI	10.1021/ma702505n
英文摘要	Fluorenyl modified N-heterocyclic carbene ligated rare earth metal bis(alkyl) complexes, (Flu-NHC)Ln(CH2SiMe3)2 (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (1a); Ln = Y (1b); Ln = Ho (1c); Ln = Lit (1d)), were synthesized and fully characterized by NMR and X-ray diffraction analyses. Complexes Ib-d with the activation of (AlBu3)-Bu-i and [Ph3C][B(C6F5)4] exhibited high activity, medium syndio-but remarkably high 3,4-regio-selectivity, and the unprecedented livingness for the polymerization of isoprene. Such distinguished catalytic performances could be maintained under various monomer-to-initiator ratios (500-5000) and broad polymerization temperatures (25-80 degrees C). The resultant polymers are crystalline, having syndiotactically enriched (racemic enchainment triad rr = 50%, pentad rrrr = 30%) 3,4-regulated (99%) microstructure and high glass-transition temperatures (40-49 degrees C. In contrast, complex la was almost inert, while complexes bearing indenyl modified N-heterocyclic carbene moiety, (Ind-NHC)Ln(CH2SiMe3)(2) (Ind-NHC = C9H6CH2CH2(NCHCCHN)C6H2Me3-2,4,6; Ln = Sc (2a); Ln = Y (2b); Ln = Ho (2c); Ln = Lit (2d)), also showed low activity or selectivity. These differences in catalytic performance could be attributed mainly to the electronics and spacial sterics of the metal center of these precursors.
语种	英语
出版者	AMER CHEMICAL SOC
WOS记录号	WOS:000254133200015
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/64733]
专题	中国科学院化学研究所
通讯作者	Cui, Dongmei
作者单位	1.Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China
推荐引用方式 GB/T 7714	Wang, Baoli,Cui, Dongmei,Lv, Kui. Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors[J]. MACROMOLECULES,2008,41(6):1983-1988.
APA	Wang, Baoli,Cui, Dongmei,&Lv, Kui.(2008).Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors.MACROMOLECULES,41(6),1983-1988.
MLA	Wang, Baoli,et al."Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors".MACROMOLECULES 41.6(2008):1983-1988.