Nature of the Entire Range of Rare Earth Metal-Based Cationic Catalysts for Highly Active and Syndioselective Styrene Polymerization

	Nature of the Entire Range of Rare Earth Metal-Based Cationic Catalysts for Highly Active and Syndioselective Styrene Polymerization
	Lin, Fei 1,2; Wang, Xingbao 3; Pan, Yupeng 1,2; Wang, Meiyan 4; Liu, Bo 1; Luo, Yi 3; Cui, Dongmei 1
刊名	ACS CATALYSIS
	2016
卷号	6 期号:1 页码:176-185
关键词	ligand design rare-earth metal complexes styrene polymerization syndiotactic DFT calculation
英文摘要	Because of the steric bulkiness and the eta(5)/kappa(1)-constrained-geometry-configuration (CGC) geometry, the entire range of pyridyl-methylene-fluorenyl-stabilized rare earth metal bisalkyl complexes, (Flu-CH2-Py)Ln(CH2SiMe3)(2)(THF)(x) (Flu = fluorenyl; Py = pyridyl; for 1, Ln = Sc and x = 0; for 2-11, Ln = Lu, Tm, Er, Ho, Y, Dy, Tb, Gd, Nd, or Pr and x = 1), and monoalkyl complex, (Flu-CH2-Py)(2)La(CH2SiMe3) (THF) (12), has been successfully achieved for the first time via the sequential salt metathesis reactions. Activated by [Ph3C] [B(C6F5)(4)] and (AlBu3)-Bu-i, complexes 1-9 showed high activity and perfect syndioselectivity for styrene polymerization, while the large Nd- and Pr-attached precursors 10 and 11 exhibited slightly decreased syndioselectivity but rather low activity; the monoalkyl La precursor 12 was completely inert. The activity increased with the decrease in the rare earth metal size, in striking contrast to the literature that has shown that a large metal facilitates a high activity, which was also not a result of an enthalpic effect (Delta H-double dagger) or an entropic effect (Delta S-double dagger) according to Eyring plots. The types of organoborates and the aluminum alkyls, the electron donors, and the polarity of the reaction medium, which affected the coordination of styrene to the active species, aroused significantly different catalytic activity, indicating that styrene coordination played the key role in the polymerization process. On the basis of this, the density functional theory calculation of the active species in the model of [(Flu-CH2-Py)Ln-nC(17)H(19)](+) revealed whenever the orbitals of the pyridyl-methylene fluorenyl ligand overlapped with those of the rare earth metals, the LUMO energy of the active species was lowered and thus the catalytic activity was high. Therefore, the LUMO energy of the active species could be adopted as a potential criterion to estimate the activity of a catalytic system for styrene polymerization. This work reveals for the first time the power of the pyridyl-methylene fluorenyl ligand and the nature of the factors influencing the catalytic performance.
收录类别	SCI
语种	英语
公开日期	2016-03-15
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/29729]
专题	化学研究所_高分子物理与化学实验室
作者单位	1.Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China 2.Univ Chinese Acad Sci, Changchun Branch, Changchun 130022, Peoples R China 3.Dalian Univ Technol, Sch Pharmaceut Sci & Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China 4.Jilin Univ, State Key Lab Theoret & Computat Chem, Inst Theoret Chem, Changchun 130022, Peoples R China
推荐引用方式 GB/T 7714	Lin, Fei,Wang, Xingbao,Pan, Yupeng,et al. Nature of the Entire Range of Rare Earth Metal-Based Cationic Catalysts for Highly Active and Syndioselective Styrene Polymerization[J]. ACS CATALYSIS,2016,6(1):176-185.
APA	Lin, Fei.,Wang, Xingbao.,Pan, Yupeng.,Wang, Meiyan.,Liu, Bo.,...&Cui, Dongmei.(2016).Nature of the Entire Range of Rare Earth Metal-Based Cationic Catalysts for Highly Active and Syndioselective Styrene Polymerization.ACS CATALYSIS,6(1),176-185.
MLA	Lin, Fei,et al."Nature of the Entire Range of Rare Earth Metal-Based Cationic Catalysts for Highly Active and Syndioselective Styrene Polymerization".ACS CATALYSIS 6.1(2016):176-185.