Preparation of new dinuclear half-titanocene complexes with ortho- and meta-xylene linkages and investigation of styrene polymerization

Linh, Nguyen Thuy Ba; Huyen, Nguyen Thi Dieu; Noh, Seok Kyun; Lyoo, Won Seok; Lee, Dong‐Ho; Kim, Yongman

doi:10.1016/j.jorganchem.2009.06.033

Cited by 16 publications

(7 citation statements)

References 26 publications

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“…Multinuclear catalysts have also been explored for tacticity control, in particular with early metals, though to a much lesser extent than mononuclear systems. , Dizirconium bis-propagators supported by amidinate ligands (G) exhibit similar stereoselectivity in the presence of ZnEt 2 to that in its absence, in contrast with monometallic catalysts, which typically exhibit lower selectivity in the presence of the chain transfer reagent . Dinuclear titanocene complexes (H) show enhanced syndiotacticity in styrene polymerization relative to the corresponding monotitanium catalysts …”

Section: Introductionmentioning

confidence: 99%

Olefin Polymerization by Dinuclear Zirconium Catalysts Based on Rigid Teraryl Frameworks: Effects on Tacticity and Copolymerization Behavior

Sampson

Choi

Akhtar³

et al. 2017

Organometallics

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Toward gaining insight into the behavior of bimetallic catalysts for olefin polymerization, a series of structurally related binuclear zirconium catalysts with bisamine bisphenolate and pyridine bisphenolate ligands connected by rigid teraryl units were synthesized. Anthracene-9,10-diyl and 2,3,5,6-tetramethylbenzene-1,4-diyl were employed as linkers. Bulky Si i Pr 3 and SiPh 3 substituents were used in the position ortho to the phenolate oxygen. Pseudo-C s and C 2 symmetric isomers are observed for the binuclear complexes of bisamine bisphenolate ligands. In general, binuclear catalysts show higher isotacticity compared to the monozirconium analogues, with some differences between isomers. Amine bisphenolate-supported dizirconium complexes were found to be moderately active (up to 1.5 kg mmol Zr −1 h −1 ) for the polymerization of 1-hexene to isotactically enriched poly-1-hexene (up to 45% mmmm) in the presence of stoichiometric trityl or anilinium borate activators. Moderate activity was observed for the production of isotactically enriched polypropylene (up to 2.8 kg mmol Zr −1 h −1 and up to 25.4% mmmm). The previously proposed model for tacticity control based on distal steric effects from the second metal site is consistent with the observed behavior. Both bisamine bisphenolate and pyridine bisphenolate supported complexes are active for the production of polyethylene in the presence of MAO with activities in the range of 1.1−1.6 kg mmol Zr −1 h −1 and copolymerize ethylene with αolefins. Little difference in the level of α-olefin incorporation is observed between mono-and dinuclear catalysts supported with the pyridine bisphenolate catalysts. In contrast, the size of the olefin affects the level of incorporation differently between monometallic and bimetallic catalysts for the bisamine bisphenolate system. The ratio of the incorporation levels with dinuclear vs mononuclear catalysts decreases with increasing comonomer size. This effect is attributed to steric pressure provided by the distal metal center on the larger olefin in dinuclear catalysts.

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Section: Introductionmentioning

confidence: 99%

Olefin Polymerization by Dinuclear Zirconium Catalysts Based on Rigid Teraryl Frameworks: Effects on Tacticity and Copolymerization Behavior

Sampson

Choi

Akhtar³

et al. 2017

Organometallics

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“…ansa -Zirconocene catalysts are the most successful systems for pairing high activity and stereoselectivity, though the development of new classes of catalysts with different selectivity and stability profiles is desirable. ,,, Thus, the design of stable and inexpensive nonmetallocene catalysts with high activity, regioselectivity, stereoselectivity, and comonomer incorporation is an active area of study. ,, Numerous nonmetallocene catalysts have been reported that exhibit either high activity or stereoselectivity, but rarely both. , Although bimetallic catalysts for olefin polymerization display a variety of beneficial effects, they have received only limited attention as a strategy for tacticity control . Improved syndioselectivity in styrene polymerization has been reported with linked dititanium systems relative to their monometallic analogues . Dipalladium catalysts have been shown to produce moderately isotactic CO/styrene copolymers, whereas the monometallic Pd system yielded stereoirregular polymers .…”

mentioning

confidence: 99%

Bimetallic Zirconium Amine Bis(phenolate) Polymerization Catalysts: Enhanced Activity and Tacticity Control for Polyolefin Synthesis

Radlauer

Agapie

2014

Organometallics

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Binucleating multidentate amine bis(phenolate) ligands with rigid terphenyl backbones were designed to support two zirconium centers locked in close proximity. Polymerizations of propylene or 1-hexene with the synthesized bimetallic precatalysts resulted in polymers with significantly higher isotacticity (up to 79% mmmm) in comparison to the stereoirregular polymers produced with previously reported Cs-symmetric monometallic analogues. The bimetallic precatalysts also display higher activity (up to 124 kg of poly(1-hexene) (mmol of Zr)−1 h–1), in comparison to the monometallic analogues, and among the highest activities reported for nonmetallocene catalysts. The stereocontrol is consistent with a bimetallic mechanism involving remote steric interactions with the ligand sphere of the second metal center.

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“…Xúc tác hai nhân half-metallocene 2, 3, 4, 5 được tổng hợp theo sơ đồ phản ứng dưới đây (Hình 2) đã được công bố [5]. Xúc tác được đánh giá cấu trúc và độ tinh khiết qua phân tích phổ cộng hưởng từ hạt nhân 1 H-NMR, 13 C-NMR, phương pháp phân tích nguyên tố (EA) và kết quả đo phù hợp với kết quả trong tài liệu tham khảo [8].…”

Section: Tổng Hợp Xúc Tác Hai Nhân Half-metallocene [Ti(η 5 -Cyclopenunclassified

“…quả nghiên cứu về tổng hợp syndiotactic polystyrene[8]. Mặc dù IBVE không có nhóm phenyl cồng kềnh như styrene, nhưng nó lại mang nhóm -OR giàu electron nên nó sẽ tương tác với nhân xúc tác để tăng độ điều hòa lập thể của PIBVE.…”

unclassified

Synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by dinuclear half-metallocene catalyst and atom transfer radical polymerization

Nguyen

Nguyen²

2015

Sci. Tech. Dev. J.

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The synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by using the combination of metallocene catalyst and atom transfer radical polymerization (ATRP) has been tried. This synthetic method takes advantages of both metallocene catalyst to form stereoregular polymer with high activity and ATRP with the controlled molecular weights and low polydispersity. The recent dinuclear half-sandwich complexes of titanium with xylene bridge, [Ti(η5-cyclopentadienyl)Cl2L]2-ortho, meta-[CH2-C6H4-CH2] (L = Cl, L = O-2,6-iPr2C6H3 ) were successfully synthesized. These catalysts were characterized by 1H NMR, 13C NMR and elemental analysis. Copolymers have been characterized by using gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). The collected copolymers have got narrow molecular weight distribution (≤1.8) and the improvement of stereoregularity (racemo dyads, r, are from 45 % to 56 %).

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Preparation of new dinuclear half-titanocene complexes with ortho- and meta-xylene linkages and investigation of styrene polymerization

Cited by 16 publications

References 26 publications

Olefin Polymerization by Dinuclear Zirconium Catalysts Based on Rigid Teraryl Frameworks: Effects on Tacticity and Copolymerization Behavior

Olefin Polymerization by Dinuclear Zirconium Catalysts Based on Rigid Teraryl Frameworks: Effects on Tacticity and Copolymerization Behavior

Bimetallic Zirconium Amine Bis(phenolate) Polymerization Catalysts: Enhanced Activity and Tacticity Control for Polyolefin Synthesis

Synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by dinuclear half-metallocene catalyst and atom transfer radical polymerization

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