Indenyl Abstraction versus Alkyl Abstraction of [(Indenyl)ScR2(thf)] by [Ph3C] [B(C6F5)4]: Aspecific and Syndiospecific Styrene Polymerization

Xu, Xin; Chen, Yaofeng

doi:10.1002/chem.200802220

Cited by 63 publications

(19 citation statements)

References 60 publications

(15 reference statements)

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“…More remarkably, with increased styrene loading from 250 to 1000 equiv, an activity up to 6.24×10 3 kg (mol Lu h) −1 was reached, which was comparable to the most active titanium and scandium systems reported (Table 1, runs 2–4) 5. 6d, 20 The resultant polystyrene retained its pure syndiotacticity ( rrrr >99 %), and the molecular weights increased linearly with the ratios, whilst the molecular weight distribution remained almost unchanged ( M w / M n =1.88–1.98). As far as we are aware, complex 1 represents the first lutetium‐based active species for syndiospecific styrene polymerization with outstanding activity.…”

Section: Resultssupporting

confidence: 60%

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Jian

Tang

Cui

2010

Chemistry A European J

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A novel linked-half-sandwich lutetium-bis(allyl) complex [(C(5)Me(4)-C(5)H(4)N)Lu(η(3)-C(3)H(5))(2)] (1) attached by a pyridyl-functionalized cyclopentadienyl ligand was synthesized and fully characterized. Complex 1 in combination with [Ph(3)C][B(C(6)F(5))(4)] exhibited unprecedented dual catalysis with outstanding activities in highly syndiotactic (rrrr>99%) styrene polymerization and distinguished cis-1,4-selective (99%) butadiene polymerization, respectively. Strikingly, this catalyst system exhibited remarkable activity (396 kg copolymer (mol(Lu) h)(-1)) for the copolymerization of butadiene and styrene. Irrespective of whether the monomers were fed in concurrent mode or sequential addition of butadiene followed by styrene, diblock copolymers were obtained exclusively, which was confirmed by a kinetics investigation of monomer conversion of copolymerization with time. In the copolymers, the styrene incorporation rate varied from 4.7 to 85.4 mol%, whereas the polybutadiene (PBD) block was highly cis-1,4-regulated (95%) and the polystyrene segment remained purely syndiotactic (rrrr>99%). Correspondingly, the copolymers exhibited glass transition temperatures (T(g)) around -107 °C and melting points (T(m)) around 268 °C; typical values for diblock microstructures. Such copolymers cannot be accessed by any other methods known to date. X-ray powder diffraction analysis of these diblock copolymers showed that the crystallizable syndiotactic polystyrene (syn-PS) block was in the toluene δ clathrate form. The AFM micrographs of diblock copolymer showed a remarkable phase-separation morphology of the cis-1,4-PBD block and syn-PS block. This represents the first example of a lutetium-based catalyst showing both high activity and selectivity for the (co)polymerization of styrene and butadiene.

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Section: Resultssupporting

confidence: 60%

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Jian

Tang

Cui

2010

Chemistry A European J

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“…Thanks to the invention of the half‐sandwich titanium catalyst that realizes high catalytic activity and syndioselectivity for styrene polymerization . Since then, extensive studies have been devoted to develop efficient “single‐site” catalytic systems for stereospecific polymerization of styrene and its derivatives, and various homogeneous metallocene, half‐metallocene, and non‐metallocene group 3 and 4 metal‐based catalysts have been invented . In the meantime, syndiotactic polystyrene derivatives bearing polar groups such as halogen, alkoxyl, aminoalkyl, and methylthio etc., that provide polymers with improved surface properties, adhesive properties, affinity for dyes, and compatibility with other polar polymers, have been successfully prepared …”

Section: Methodsmentioning

confidence: 99%

Syndioselective Polymerization of Vinylnaphthalene

Yan

Zhang

et al. 2019

Macromol. Rapid Commun.

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Coordination polymerizations of 1‐vinylnaphthalene (1VN), 2‐vinylnaphthalene (2VN) and 6‐methoxy‐2‐vinylnaphthalene (MVN) are carried out at room temperature by using the half‐sandwich scandium precursor FluSiMe3Sc(CH2SiMe3)2(THF) (1) and the constrained geometry configuration rare‐earth metal precursors FluCH2PyLn(CH2SiMe3)2(THF)n [Flu = C13H8, Py = C5H4N; Ln = Sc (2a), n = 0; Ln = Lu (2b), Y(2c), n = 1]. Atactic poly(1VN) and perfect syndiotactic poly(2VN) and poly(MVN) are produced by precursors 2a‐2c in a controlled way. Treatment of poly(MVN) with boron tribromide at −20 °C provides a syndiotactic poly(6‐hydroxy‐2‐vinylnaphthalene).

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“…Similar monocyclopentadienyl scandium complexes with benzyl groups (254) or borohydride groups (255) and those with different silyl groups on the Cp group (256) are also effective. The polymerization by using the indenyl scandium complex (65) affords syndiotactic and/or atactic polystyrene depending on the substituents on the indenyl group (257). The complex with R 1 = R 3 = SiMe 3 , R 2 = H affords the syndiotactic polymer, where the active species is the cationic indenyl Sc complex.…”

Section: Syndiospecific Polymerization Of Styrenementioning

confidence: 99%

Stereoregular Polymers

Takeuchi

2013

Encyclopedia of Polymer Science and Technology

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Control of structure of polymers is an important issue in polymer synthesis because it affects properties such as solubility, crystallinity, and thermal properties. The polymers having stereogenic centers on a main chain can be synthesized by vinyl polymerization of olefinic monomers or ring-opening polymerization of cyclic monomers. Control of trans-cis selectivity is also important for the polymers containing C C double bonds in the main chain. The progress of homogeneous metal complex catalysts for coordination and ring-opening polymerization enables tailor-made control of the stereoregularity of the polymers. In this article, general aspects of stereoregular polymers, especially the polymer of monosubstituted vinyl monomers, are described. Recent progress in stereospecific polymerization of propylene, α-olefins, and styrenes is also summarized. Propylene Polymerization.Isospecific Polymerization of Propylene by Ziegler-Natta Catalysts. In 1954, Natta found that TiCl 3 /Et 2 AlCl catalyst is effective for the synthesis of isotactic polypropylene (4,5). Ti(III) is the active species of the polymerization, whereas other Ti species are also included in the catalyst. Moreover, the stereospecific Ti(III) site as well as nonstereospecific Ti(III) site exists in the catalyst.

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Indenyl Abstraction versus Alkyl Abstraction of [(Indenyl)ScR₂(thf)] by [Ph₃C] [B(C₆F₅)₄]: Aspecific and Syndiospecific Styrene Polymerization

Cited by 63 publications

References 60 publications

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

A Lutetium Allyl Complex That Bears a Pyridyl‐Functionalized Cyclopentadienyl Ligand: Dual Catalysis on Highly Syndiospecific and cis‐1,4‐Selective (Co)Polymerizations of Styrene and Butadiene

Syndioselective Polymerization of Vinylnaphthalene

Stereoregular Polymers

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