Synthesis of Cyclic Polyolefin: <scp>Ring‐Opening</scp> Metathesis Polymerization by Binuclear Vanadium Complexes<sup>†</sup>

Hou, Xiaohua; Chen, Xiaojian; Gao, Xiang; Lei, Xu; Zhou, Li; Wu, Zong‐Quan

doi:10.1002/cjoc.202000636

Cited by 11 publications

(4 citation statements)

References 27 publications

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“…Also, ring expansion metathesis polymerization was recently reported by the Wu group. [49] A series of different binuclear V complexes were synthesized and determined to have high activity in the formation of cyclic polymers.…”

Section: Vanadiummentioning

confidence: 99%

Olefin Metathesis by First‐Row Transition Metals

2021

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Catalytic olefin metathesis based on the second-and third-row transition metals has become one of the most powerful transformations in modern organic chemistry. The shift to firstrow metals to produce fine and commodity chemicals would be an important achievement to complement existing methods with inexpensive and greener alternatives. In addition, those systems can offer unusual reactivity based on the unique electronic structure of the base metals. In this Minireview, we summarize the progress of the development of alkylidenes and metallacycles of first-row transition metals from scandium to nickel capable of performing cycloaddition and cycloreversion steps, crucial reactions in olefin metathesis. In addition, we will discuss systems capable of performing olefin metathesis; however, the nature of active species is not yet known.

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Section: Vanadiummentioning

confidence: 99%

Olefin Metathesis by First‐Row Transition Metals

2021

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“…[ 10‐17 ] These non‐metallocene catalysts can show high activity, great control on molecular weight ( M w ) and distribution and produce distinctive polyolefins that are difficult to prepare by heterogeneous catalysts or conventional metallocene catalysts. [ 18‐26 ]…”

Section: Background and Originality Contentmentioning

confidence: 99%

Titanium Complexes Bearing NNO‐Tridentate Ligands: Highly Active Olefin Polymerization Catalysts with Great Control on Molecular Weight and Distribution^†

et al. 2022

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A series of titanium amido complexes (1-Ti(NMe 2 ) 2 to 4-Ti(NMe 2 ) 2 ) bearing NNO-tridentate ligands was synthesized from the reactions of phenoxy-imine-amine ligands with one equivalent of Ti(NMe 2 ) 4 . Subsequently, titanium dichloride complexes (1-TiCl 2 to 4-TiCl 2 ) were prepared by treatment of titanium amido complexes with excess Me 3 SiCl in toluene. All metal complexes were characterized by 1 H and 13 C NMR spectroscopy, and the molecular structures of complexes of 2-Ti(NMe 2 ) 2 , 2-TiCl 2 , and 4-TiCl 2 in the solid state were determined by single-crystal X-ray diffraction. Upon activation with MAO, titanium dichloride complexes as single-site catalysts were extremely active toward ethylene homopolymerization with great control on molecular weight and distribution. In particular, 3-TiCl 2 /MAO exhibited an activity as high as 1.35 × 10 8 g(PE)•mol −1 (Ti)•h −1 at 70 °C and produced polyethylene with high molecular weight (41.7 × 10 4 g•mol −1 ) and very narrow distribution (Đ = 1.23). In the presence of 1-octene as comonomer, linear low-density polyethylenes (LLDPEs) with ultrahigh molecular weights (M w = 136-326 × 10 4 g•mol −1) and narrow distributions (Đ = 1.20-1.50) were successfully synthesized.

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“…Precise control over the polymer architecture was always a fascinating subject, and it continued to inspire polymer chemistry to develop various topologies, such as star-shaped, − hyperbranched, dendronized, and cyclic polymers. − Among them, cyclic polymers often exhibit unique performance as a result of the absence of chain ends, such as smaller hydrodynamic volume and radius of gyration, higher glass transition temperature, and lower intrinsic viscosity, − compared to their linear counterparts with similar molecular weight. Thus, cyclic polymers possessing sun-, − cage-, tadpole-, − eight-, − manacle-, and paddle-shaped architectures have attracted increasing interest.…”

Section: Introductionmentioning

confidence: 99%

Efficient Synthesis and Cyclic Molecular Topology of Ultralarge-Sized Bicyclic and Tetracyclic Polymers

Quan

Zhang

et al. 2022

Macromolecules

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Cyclic polymers have been extensively studied because of their unique topology and physical properties, while the methods for efficient synthesis of well-defined bicyclic and multicyclic polymers are limited. Herein, an effective strategy was developed to synthesize ultralarge-sized bicyclic polymers by a ring-opening metathesis polymerization (ROMP)-based blocking-cyclization technique in a simplified feeding procedure, using the short ladderphane bearing four living ends as the initial motif. The molecular topology of the bicyclic polymer was clarified by pieces of evidence and validated by theoretical simulation. Importantly, the visualized eight-shaped molecular topology was observed. Meanwhile, the bicyclic polymer exhibited stronger thermal, fluorescence emission, and mechanical properties and better dielectric and energy storage performance than its four-arm counterpart, which elucidated the difference in molecular topology between bicyclic and four-arm polymers. Moreover, a tetracyclic polymer with a large ring size could be readily obtained. Therefore, this designed strategy opens new horizons for building bicyclic and multicyclic polymers using the conventional ROMP and commercial Grubbs catalyst.

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Synthesis of Cyclic Polyolefin: Ring‐Opening Metathesis Polymerization by Binuclear Vanadium Complexes^†

Cited by 11 publications

References 27 publications

Olefin Metathesis by First‐Row Transition Metals

Olefin Metathesis by First‐Row Transition Metals

Titanium Complexes Bearing NNO‐Tridentate Ligands: Highly Active Olefin Polymerization Catalysts with Great Control on Molecular Weight and Distribution^†

Efficient Synthesis and Cyclic Molecular Topology of Ultralarge-Sized Bicyclic and Tetracyclic Polymers

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Synthesis of Cyclic Polyolefin: Ring‐Opening Metathesis Polymerization by Binuclear Vanadium Complexes†

Cited by 11 publications

References 27 publications

Olefin Metathesis by First‐Row Transition Metals

Olefin Metathesis by First‐Row Transition Metals

Titanium Complexes Bearing NNO‐Tridentate Ligands: Highly Active Olefin Polymerization Catalysts with Great Control on Molecular Weight and Distribution†

Efficient Synthesis and Cyclic Molecular Topology of Ultralarge-Sized Bicyclic and Tetracyclic Polymers

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Product

Resources

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Synthesis of Cyclic Polyolefin: Ring‐Opening Metathesis Polymerization by Binuclear Vanadium Complexes^†

Titanium Complexes Bearing NNO‐Tridentate Ligands: Highly Active Olefin Polymerization Catalysts with Great Control on Molecular Weight and Distribution^†