Rare-earth metal bis(alkyl)s that bear a 2-pyridinemethanamine ligand: Dual catalysis of the polymerizations of both isoprene and ethylene

doi:10.1039/c1dt11890k

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	Rare-earth metal bis(alkyl)s that bear a 2-pyridinemethanamine ligand: Dual catalysis of the polymerizations of both isoprene and ethylene
	Jian, Zhongbao 1,2; Cui, Dongmei 1
刊名	DALTON TRANSACTIONS
	2012
卷号	41 期号:8 页码:2367-2373
ISSN号	1477-9226
DOI	10.1039/c1dt11890k
英文摘要	New pyridinemethanamido-ligated rare-earth metal bis(alkyl) complexes [C5H4N-CH(Me)NC6H3(Pr-i)(2)] Ln(CH2SiMe3)(2)(THF) (Ln = Sc (1), Y (2), Lu (3)) have been prepared at 0 degrees C via a protonolysis reaction between rare-earth metal tris(alkyl)s and the corresponding 2-pyridinemethanamine ligand and fully characterized by NMR and X-ray diffraction analysis. Bis(alkyl) complexes 1-3 are analogous monomers of THF solvate, where the ligand bonds to the metal center in a kappa N: kappa N-bidentate mode. Complexes 1-3, in combination with [Ph3C][B(C6F5)(4)], showed a good activity towards isoprene polymerization to give polyisoprene with a main 3,4-selectivity (60%-66%); in particular the yttrium catalyst system, 2/[Ph3C][B(C6F5)(4)], displayed a living mode. By contrast, only the precatalyst 2 exhibited activity for isoprene polymerization in the presence of [PhNMe2H][ B(C6F5) 4]. The influence of alkylaluminium (AlR3, R = Me, Et, Bu-i) and the metal center on the polymerization of isoprene was also studied, and it was found that addition of AlMe3 to the catalyst systems could lead to a dramatic change in the microstructure of the polymer from 3,4-specific to 1,4-selective (89%-95%), but the ionic radius of the central metal had little influence on the selectivity. In addition, by using the 1(Sc)/[Ph3C][B(C6F5)(4)]/10 (AlBu3)-Bu-i, the polymerization of ethylene was also achieved with moderate activity (up to 3.2 105 g (PE) mol(Sc)(-1) h(-1) bar(-1)) and narrow polydispersity (M-w/M-n = 1.19-1.28); while the effect of temperature on the activity was discussed. Such dual catalysis for the polymerizations of both isoprene and ethylene is rare.
语种	英语
出版者	ROYAL SOC CHEMISTRY
WOS记录号	WOS:000300186100021
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/49841]
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	Jian, Zhongbao,Cui, Dongmei. Rare-earth metal bis(alkyl)s that bear a 2-pyridinemethanamine ligand: Dual catalysis of the polymerizations of both isoprene and ethylene[J]. DALTON TRANSACTIONS,2012,41(8):2367-2373.
APA	Jian, Zhongbao,&Cui, Dongmei.(2012).Rare-earth metal bis(alkyl)s that bear a 2-pyridinemethanamine ligand: Dual catalysis of the polymerizations of both isoprene and ethylene.DALTON TRANSACTIONS,41(8),2367-2373.
MLA	Jian, Zhongbao,et al."Rare-earth metal bis(alkyl)s that bear a 2-pyridinemethanamine ligand: Dual catalysis of the polymerizations of both isoprene and ethylene".DALTON TRANSACTIONS 41.8(2012):2367-2373.