Nickel complexes based on hyperbranched salicylaldimine ligands: Synthesis, characterization, and catalytic properties for ethylene oligomerization

Wang, Jun; Zhang, Na; Li, Cui Qin; Shi, Weiguang; Lin, Zhi Yu

doi:10.1016/j.jorganchem.2016.08.022

Cited by 26 publications

(8 citation statements)

References 24 publications

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“…Increasing the carbon chain length in both positions (n and R) leads to less soluble pre-catalysts, and thus decreases the rate of oligomerization (49a-c). [134][135][136] Replacing the linear alkyl R 49c with a cyclic alkyl 49d induces higher activity of the catalytic system without changing the selectivity (Table 6, example for 49d). 137 Bidentate phenoxide-iminophosphorane nickel(II) complexes 50 and 51 (Figure 27 The complexes 50 and 51 were evaluated and compared for the catalytic oligomerization of ethylene in the presence of AlEt 2 Cl.…”

Section: Figure 26 Salicylaldimine-based Nickel(ii) Complexesmentioning

confidence: 99%

Nickel Catalyzed Olefin Oligomerization and Dimerization

et al. 2020

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Brought to life more than half a century ago and successfully applied for high-value petrochemical intermediates production, nickel-catalyzed olefin oligomerization is still a very dynamic topic, with many fundamental questions to address and industrial challenges to overcome. The unique and versatile reactivity of nickel enables the oligomerization of ethylene, propylene and butenes into a wide range of oligomers that are highly sought-after in numerous fields to be controlled. Interestingly, both homogeneous and heterogeneous nickel catalysts have been scrutinized and employed to do this. This rare specificity encouraged us to interlink them in this review so as to open up opportunities for further catalyst development and innovation. An in-depth understanding of the reaction mechanisms in play is essential to being able to fine-tune the selectivity and achieve efficiency in the rational design of novel catalytic systems. This review thus provides a complete overview of the subject, compiling the main fundamental/industrial milestones and remaining challenges facing homogeneous/heterogeneous approaches as well as emerging catalytic concepts, with a focus on the last 10 years.

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Section: Figure 26 Salicylaldimine-based Nickel(ii) Complexesmentioning

confidence: 99%

Nickel Catalyzed Olefin Oligomerization and Dimerization

et al. 2020

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“…In our previous works, mononuclear and binuclear (α‐diimine) nickel(II) complexes based the Schiff‐based ligands were found that the oligomerization experiments were limited below 30 min [ 34 ] and increasing the reaction time led to the decrease of the catalytic activity in ethylene oligomerization. However, the maximum catalytic activity of 17.62 × 10 5 g/(mol Ni•h) was observed at 60 min for the PS‐Ni complex (Figure 12), which was due to the confinement effect and conjugated effect of the PS‐ligand.…”

Section: Resultsmentioning

confidence: 99%

Polynuclear (α‐diimine) nickel(II) complex as catalyst for ethylene oligomerization

Guo

et al. 2021

Applied Organom Chemis

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Late transition metal catalysts with single or multiple active centers have great attention in the ethylene oligomerization application owing to their unique properties. A new polynuclear (α‐diimine) nickel(II) complex (PS‐Ni complex) bearing the conjugated poly(Schiff‐base) ligand (PS‐ligand) was synthesized. The structures and the composition of the PS‐ligand and the PS‐Ni complex were characterized by Fourier transform infrared (FTIR) analysis, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric (TG) analysis, nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The PS‐Ni complex was used as precatalyst in ethylene oligomerization combined with methylaluminoxane (MAO) and has good catalytic activity for ethylene oligomerization under mild conditions. Compared with the corresponding mononuclear (α‐diimine) nickel(II) complex, the PS‐Ni complex showed higher activity of 17.62 × 105 g/(mol Ni•h), and the main products were C4 and C6 olefins in cyclohexane when the dosage of precatalyst was 2 μmol, the Al/Ni molar ratio was 500, the ethylene pressure was 0.5 MPa, the reaction time was 60 min, and the reaction temperature was 25°C. The main oligomers were α‐olefins, and the selectivity was up to 98.68%, due to the more electron‐deficient catalytic centers of the conjugated structure of poly(Schiff‐base) ligand.

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“…The solid-state diffuse UV-vis spectrum of the PD-(NH 2 ) 6 ligand showed five absorption bands at 208, 224, 266, 298 and 382 nm, respectively. The bands at 208 and 224 nm were assigned to the K band of the benzene ring, and the bands at 266 and 298 nm to the B band of the benzene ring [30]. The band at 382 nm corresponded to the R band of n → π* transition for P=N.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Synthesis and ethylene oligomerization behavior of trinuclear nickel complex with phosphorus dendrimer

et al. 2021

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A phosphorus dendrimer with multiple amino groups was synthesized via a two-step reaction with phosphonitrilic chloride trimer and 4-acetamidophenol. The trinuclear nickel complex was subsequently prepared with the phosphorus dendrimer and nickel chloride hexahydrate as starting materials. The structures of the phosphorus dendrimer and the trinuclear nickel complex were characterized by physicochemical and spectroscopic methods. The trinuclear nickel complex based on the phosphorus dendrimer was evaluated as catalyst precursor for ethylene oligomerization using methylaluminoxane (MAO) as an activator. Under the conditions of 0.5 h, 0.9 MPa, 25 °C and Al/Ni molar ratio of 700, the catalytic activity of the trinuclear nickel complex showed a maximum value of 2.31 × 10 5 g/(mol Ni h), and the oligomerization products were mainly low-carbon olefins (C 4 and C 6 ). The ligand structure and the coordination mode showed notable variations in the catalytic activities and the product distribution due to the influence of electronic and steric effects. The catalytic activity of the nickel complex based on the ligand with an aryl backbone was superior to the nickel complex based on the ligand with an alkyl backbone.

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Nickel complexes based on hyperbranched salicylaldimine ligands: Synthesis, characterization, and catalytic properties for ethylene oligomerization

Cited by 26 publications

References 24 publications

Nickel Catalyzed Olefin Oligomerization and Dimerization

Nickel Catalyzed Olefin Oligomerization and Dimerization

Polynuclear (α‐diimine) nickel(II) complex as catalyst for ethylene oligomerization

Synthesis and ethylene oligomerization behavior of trinuclear nickel complex with phosphorus dendrimer

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