Highly active and thermo‐stable iminopyridyl vanadium oxychloride catalyzed isoprene polymerization

Zhao, Mengmeng; Wang, Liang; Mahmood, Qaiser; Jing, Chuyang; Zhu, Guangqian; Zhang, Xianhui; Chen, Xiao; Wang, Qinggang

doi:10.1002/pol.20200291

Cited by 9 publications

(4 citation statements)

References 64 publications

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“…Iminopyridyl vanadium oxychloride complexes, in combination with MAO, were found to be highly thermostable, exhibiting excellent activity even at 100 °C (up to 408 kg polyisoprene (mol V) −1 h –1 ) and giving polyisoprenes with a high cis content (up to 75%), with 25% side-chain 3,4 functional groups, which is particularly useful to enhance the application of these synthetic rubbers (Figure ).…”

Section: Catalysts Based On Transition Metal and Lanthanide Complexes...mentioning

confidence: 99%

Dienes Polymerization: Where We Are and What Lies Ahead

Ricci¹,

Pampaloni

Sommazzi

et al. 2021

Macromolecules

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Recently, the research activity in the field of the stereospecific polymerization of conjugated dienes has focused on the use of catalysts based on organometallic complexes having a well-defined structure and containing ligands of various types (e.g., phosphines, bis-imines, and pyridylimines), since it has been observed that the nature of the ligand, as expected on the basis of the diene polymerization mechanism proposed several years ago by Porri, is able to exert a strong influence on the polymerization regioand stereoselectivity, on the polymer molecular weights and their distribution, and in some cases to impart a living feature to the catalysts themselves. In this Perspective we highlight the most recent results obtained in this field and discuss possible future developments in this area.

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Section: Catalysts Based On Transition Metal and Lanthanide Complexes...mentioning

confidence: 99%

Dienes Polymerization: Where We Are and What Lies Ahead

Ricci¹,

Pampaloni

Sommazzi

et al. 2021

Macromolecules

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“…Moreover, the 1 H and 13 C NMR spectra of polymers prepared at different Al/Fe ratios exhibited no significant change in the mode of monomer insertion with variations in the cocatalyst amount. The resulting polyisoprenes primarily consisted of 1,4 (≈ 61 mol %) and 3,4 units (≈ 36 mol %), along with a small fraction of trans -1,4 additions. , These results indicated that the amount of cocatalyst significantly influences the catalytic activity, molecular weight, and molecular weight distributions of polyisoprene. However, the selectivity of monomer addition remained mainly unaffected.…”

Section: Resultsmentioning

confidence: 79%

Cycloheptyl-Fused Iminopyridine-Iron Catalysts for Isoprene Polymerization with Enhanced Activity and Thermal Stability

Yuan,

Ren,

Mahmood

et al. 2023

Organometallics

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In this study, a set of six cycloheptyl-fused iminopyridine-ligated iron complexes were prepared and investigated for isoprene polymerization under various reaction conditions. These complexes have been prepared either through a one-pot process or via ligand synthesis prior to complex formation. Both methods resulted in structurally equivalent iron complexes in good yields, as confirmed by X-ray diffraction, FTIR spectra, elemental analysis, and ESI mass spectrometry. Upon activation with MAO, all complexes were active catalysts for isoprene polymerization. Systematic variations in the steric hindrance of ligand ortho-substituent and reaction conditions exhibited significant effects on polymerization activity and polymer properties. The catalyst with less steric hindrance showed remarkable activity and produced high molecular weight polyisoprene but was less selective. Conversely, sterically encumbered catalysts were less active but more selective in both regio-and stereoselectivity. Particularly, Fe1 exhibited high polymerization activities, achieving as high as 1.2 × 10 8 g (mol of cat.) −1 h −1 over a period of less than 1 min, with complete monomer conversion. Moreover, this catalyst demonstrated high thermal stability, achieving good to excellent monomer conversions over a wide temperature range of −25 to 100 °C, and the resultant polyisoprenes consistently maintained the molecular weight level of approximately 10 5 g mol −1 across all reaction temperatures. Notably, the polyisoprene predominantly consisted of 1,4 and 3,4 configurations in the range of 55−71 and 29−45 mol %, respectively, while 1,4 units showed remarkably high cis stereoselectivity (cis-1,4/trans-1,4: >99/1).

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“…2,[8][9][10][11][12][13] Afterward, with the discovery of methylaluminoxane (MAO), various transition metal-based metallocene and non-metallocene catalysts with well-defined chemical structures have been investigated. Many complexes based on Ti, [14][15][16] Sc, [17][18][19][20] Y, [21][22][23] Cr, 24,25 V, [26][27][28] Co, 29,30 Fe, [31][32][33] etc. provide extremely high activity and stereospecificity when combined with MAO or boron compounds.…”

Section: Introductionmentioning

confidence: 99%

Pyridine-amido aluminum catalyst precursors for 1,3-butadiene transition-metal-free stereospecific polymerization

et al. 2023

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Highly active and thermo‐stable iminopyridyl vanadium oxychloride catalyzed isoprene polymerization

Abstract: Stereoregular polymerizations are of high importance, which disclosing the relationships between microstructures and physical properties of polymers. In this contribution, a series of iminopyridyl vanadium oxychloride complexes V1-V8

Cited by 9 publications

References 64 publications

Dienes Polymerization: Where We Are and What Lies Ahead

Dienes Polymerization: Where We Are and What Lies Ahead

Cycloheptyl-Fused Iminopyridine-Iron Catalysts for Isoprene Polymerization with Enhanced Activity and Thermal Stability

Pyridine-amido aluminum catalyst precursors for 1,3-butadiene transition-metal-free stereospecific polymerization

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