Influence of intramolecular π–π and H-bonding interactions on pyrazolylimine nickel-catalyzed ethylene polymerization and co-polymerization

Sun, Yao; Chi, Mingjun; Bashir, Muhammad Sohail; Wang, Yusong; Qasim, Muhammad

doi:10.1039/d1nj02437j

Cited by 6 publications

(4 citation statements)

References 61 publications

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“…In addition to α-diimine type catalysts, π–π interactions are also observed in pyrazolylimine nickel catalysts 22 (Figure ) between the backbone phenyl and the phenyl of the benzhydryl group . Compared to previously reported pyrazolylimine catalysts without π–π interactions, the π–π interactions are found to contribute to a higher thermal stability of the catalyst (up to 80 °C) and 40 times higher molecular weight.…”

Section: π–π Interactionsmentioning

confidence: 74%

Noncovalent Interactions in Late Transition Metal-Catalyzed Polymerization of Olefins

Zheng,

Gao

2024

Macromolecules

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Transition metal-catalyzed olefin polymerization dominates in the polyolefin field, and we still have limited control over a catalyst's behavior. In addition to traditional steric and electronic modifications, developing new design strategies for transition metal catalysts is highly intriguing and may open avenues for the highly efficient synthesis of new highperformance polyolefins. In this Perspective, recent advances in weak noncovalent interactions including hydrogen bonding, π−π interactions, metal−aryl π-interactions, and electrostatic metal−X interactions (X = heteroatoms) for modulating late transition metal-catalyzed polymerization of olefins are reviewed with an emphasis on their influences on (co)polymerization of olefins. It provides a practical consultation for polymer synthesis chemists that are interested in developing weak noncovalent interaction-assisted polymerization of olefins.

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Section: π–π Interactionsmentioning

confidence: 74%

Noncovalent Interactions in Late Transition Metal-Catalyzed Polymerization of Olefins

Zheng,

Gao

2024

Macromolecules

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“…Imine based late‐transition metal catalysts have a distinctive status in ethylene home and co‐polymerization 1–3 . A range of ligands such as, α ‐diimine, 4–10 salicylaldimines, 11–18 imino‐pyridyl, 19–25 keto‐imine, 26,27 iminopyridine‐ N ‐oxide, 28,29 pyrrole‐imines 30 and pyrazolyl‐imines 31–33 have been synthesized by simple condensation method. A literature survey revealed that, any structural modification either in the amines or carbonyl containing backbone has characteristic influence not only on the catalyst performance but also on the polymer properties such as, molecular weight and microstructure 34–43 .…”

Section: Introductionmentioning

confidence: 99%

Ethylene homo and co‐polymerization catalyzed by extensively bulky nickel catalysts with shielding wings of chlorine atoms

Ahmad,

Wang,

Tian

et al. 2024

Journal of Polymer Science

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Designing the catalysts to get high molecular weight polyethylene is an art. The catalysts bearing imine functionality derived from 8‐arylnaphthyl amines are more impressive and attractive in this regard. In this work, we synthesize 2,4‐dibenzhydryl‐8‐(3,5‐dichlorophenyl)naphthalen‐1‐amine to condense with picolinaldehyde, pyridine‐N‐oxide‐2‐carbaldehyde and 3,4‐dibutanone and then subsequently the treatment of resulting ligands with nickel precursors to get the corresponding catalysts. It was hypothesized that 3,5‐dichlorophenyl having extended wings of chlorine atoms along with bulky dibenzhydryl groups can provide good shielding on both apical positions of metal in response to slow down the chain transfer. More interestingly, the polymerization was done in industrially claimed n‐heptane solvent. All the catalysts showed activity in an order of 106, whereas a value of 1.04 × 107 g mol−1 h−1 has been recorded from keto‐imine based Ni‐3 catalyst. All catalysts generates polymer with high molecular weight with maximum value was recorded by Ni‐2 up to 37.4 × 104 g mol−1. Ni‐3 can also incorporate methyl 10‐undecenoate up to 2.6% in polyethylene backbone.

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“…For example, [N, N] type catalysts such as α-diimine nickel can prepare polyolefins with branched chain structures and various polymer topologies due to their unique chain walking mechanism. 35,36 [N, O] type catalysts such as phenoxyminato nickel catalysts and α-imino-ketone nickel catalysts also showed chain walking feature. [37][38][39][40][41][42][43][44] In contrast, [P, O] type catalysts such as shell higher olefn process (SHOP) catalyst 45 (Chart 1A) and phosphine-sulfonate nickel 46 (Chart 1B) mainly produced linearly structured polyolefins.…”

Section: Introductionmentioning

confidence: 99%

Ethylene homo and copolymerization by phosphorus‐benzoquinone based homogeneous and heterogeneous nickel catalysts

Wang

et al. 2022

Journal of Polymer Science

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The low cost and high abundancy of nickel makes it highly attractive for both industrial and academic researchers in the field of polyolefin. However, the development of high performance nickel catalysts for ethylene homo and copolymerization is highly challenging. In this contribution, two novel cationic nickel catalysts with quinone backbone and sterically hindered aryl substituents on phosphine have been synthesized and supported on solid supports to prepare heterogeneous catalysts. The homogeneous catalysts showed high activity and high thermal stability in ethylene polymerization. After heterogenization of these catalysts, all the polymerization parameters (polymerization activity, thermal stability, and polymer molecular weight) were significantly improved. The heterogeneous catalyst can achieve activity of up to 3.26 × 106 g mol−1 h−1, along with polyethylene molecular weight of up to 81.8 × 104 g mol−1. More importantly, these homogeneous and heterogeneous catalysts can realize copolymerization of ethylene with a series of polar comonomers such as methyl 10‐undecenoate, 10‐undecenol, and 6‐chloro‐1‐hexene.

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Influence of intramolecular π–π and H-bonding interactions on pyrazolylimine nickel-catalyzed ethylene polymerization and co-polymerization

Abstract: Designing of new catalysts through structural modification, is a permanent dimension in catalysis. In this scenario, the limitations of pyrazolylimine, concerning to their low thermal stability and providing the polymer...

Cited by 6 publications

References 61 publications

Noncovalent Interactions in Late Transition Metal-Catalyzed Polymerization of Olefins

Noncovalent Interactions in Late Transition Metal-Catalyzed Polymerization of Olefins

Ethylene homo and co‐polymerization catalyzed by extensively bulky nickel catalysts with shielding wings of chlorine atoms

Ethylene homo and copolymerization by phosphorus‐benzoquinone based homogeneous and heterogeneous nickel catalysts

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