Neodymium(III) Complexes with Bulky ansa-Bis(cyclopentadienyl) Ligands: Synthesis and Use in Olefin Oligomerization
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- 作者：Sté ; phane Bogaert ; Thomas Chenal ; André ; Mortreux ; Guy Nowogrocki ; Christian W. Lehmann ; and Jean-Franç ; ois Carpentier
- 刊名：Organometallics
- 出版年：2001
- 出版时间：January 8, 2001
- 年：2001
- 卷：20
- 期：1
- 页码：199 - 205
- 全文大小：108K
- 年卷期：v.20,no.1(January 8, 2001)
- ISSN：1520-6041
文摘
The trivalent neodymium complexes [rac-{Me2Si(
5-2-SiMe3-4-t-Bu-C5H2)2}Nd(
-Cl)2Li(THF)2] (rac-3), [rac-{Me2Si(5-2,4-(SiMe3)2C5H2)2}Nd(-Cl)2Li(THF)2] (rac-5), and [{Me2Si(5-2,4-(SiMe3)2C5H2)(5-3,4-(SiMe3)2C5H2)}Nd(-Cl)2Li(THF)2] (C1-6) have been prepared andtheir structures investigated by NMR and X-ray crystallography. These new chlorolanthanocenes, when combined in situ with a dialkylmagnesium cocatalyst, initiate the polymerization of ethylene and 1-octene to yield di(oligoalkyl)magnesium species, which can be finallyhydrolyzed to oligomers. Bulky bridged complexes rac-3, rac-5, and C1-6 gave significantlymore active catalysts for 1-octene oligomerization (Mn = 400-1300, Mw/Mn = 1.11-1.65)than systems based on nonbridged complexes [(5-C5Me5)2Nd(-Cl)2Li(Et2O)2] (1) and [(5-1,3-(SiMe3)2C5H3)2Nd(-Cl)2Li(THF)2] (7). Ethylene oligomerization (Mn = 400-5000) wasbest achieved with complexes 1 and rac-3, as important catalyst decay occurred with bridgedbis(trimethylsilyl) systems rac-5 and C1-6.
5-2-SiMe3-4-t-Bu-C5H2)2}Nd(-Cl)2Li(THF)2] (rac-3), [rac-{Me2Si(5-2,4-(SiMe3)2C5H2)2}Nd(-Cl)2Li(THF)2] (rac-5), and [{Me2Si(5-2,4-(SiMe3)2C5H2)(5-3,4-(SiMe3)2C5H2)}Nd(-Cl)2Li(THF)2] (C1-6) have been prepared andtheir structures investigated by NMR and X-ray crystallography. These new chlorolanthanocenes, when combined in situ with a dialkylmagnesium cocatalyst, initiate the polymerization of ethylene and 1-octene to yield di(oligoalkyl)magnesium species, which can be finallyhydrolyzed to oligomers. Bulky bridged complexes rac-3, rac-5, and C1-6 gave significantlymore active catalysts for 1-octene oligomerization (Mn = 400-1300, Mw/Mn = 1.11-1.65)than systems based on nonbridged complexes [(5-C5Me5)2Nd(-Cl)2Li(Et2O)2] (1) and [(5-1,3-(SiMe3)2C5H3)2Nd(-Cl)2Li(THF)2] (7). Ethylene oligomerization (Mn = 400-5000) wasbest achieved with complexes 1 and rac-3, as important catalyst decay occurred with bridgedbis(trimethylsilyl) systems rac-5 and C1-6.