scholarly journals Co‐catalyst effects on the thermal stability/activity of N,N,N ‐Co ethylene polymerization Catalysts Bearing Fluoro‐Substituted N‐2,6‐dibenzhydrylphenyl groups

2019 ◽  
Vol 33 (10) ◽  
Author(s):  
Qiuyue Zhang ◽  
Yanping Ma ◽  
Hongyi Suo ◽  
Gregory A. Solan ◽  
Tongling Liang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ethylene Polymerization ◽  
Polymerization Catalysts ◽  
Co Catalyst

Bis-cycloheptyl-fused bis(imino)pyridine-cobalt catalysts for PE wax formation: positive effects of fluoride substitution on catalytic performance and thermal stability

2020 ◽  
Vol 49 (27) ◽  
pp. 9425-9437 ◽  
Author(s):  
Qiuyue Zhang ◽  
Ningning Wu ◽  
Junfeng Xiang ◽  
Gregory A. Solan ◽  
Hongyi Suo ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Catalytic Performance ◽  
Cobalt Catalysts ◽  
Low Molecular Weight ◽  
Polymerization Catalysts ◽  
Positive Effects

The depicted ethylene polymerization catalysts exhibited optimal activities at 60 °C forming low molecular weight PE waxes; ortho-F substitution proved beneficial.

Thermally resilient cobalt ethylene polymerization catalysts under the joint influence of co-catalyst, gem-dimethyl substitution and ortho-cycloalkyl ring size

Polymer ◽  
2021 ◽  
Vol 222 ◽  
pp. 123684
Author(s):  
Randi Zhang ◽  
Yongfeng Huang ◽  
Yanping Ma ◽  
Gregory A. Solan ◽  
Xinquan Hu ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Ring Size ◽  
Polymerization Catalysts ◽  
Co Catalyst ◽  
Joint Influence

Doubly fused N,N,N-Iron Ethylene Polymerization Catalysts appended with Fluoride Substituents; probing catalytic performance via a combined experimental and MLR study

2021 ◽  
Author(s):  
Qiuyue Zhang ◽  
Wenhong Yang ◽  
Zheng Wang ◽  
Gregory A. Solan ◽  
Tongling Liang ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Catalytic Performance ◽  
Chloride Complex ◽  
Polymerization Catalysts

Access to six examples of α,α’-bis(imino)-2,3:5,6-bis(pentamethylene)pyridine-iron(II) chloride complex, [2,3:5,6-{C4H8C(N(2-R1-4-R3-6-R2C6H2)}2C5HN] (R1 = Me, R2 = R3 = CH(p-FPh)2 Fe1; R1 = Et, R2 = R3 = CH(p-FPh)2 Fe2; R1 = iPr,...

scholarly journals Molecular weight control in organochromium olefin polymerization catalysis by hemilabile ligand–metal interactions

2016 ◽  
Vol 12 ◽  
pp. 1372-1379 ◽  
Author(s):  
Stefan Mark ◽  
Hubert Wadepohl ◽  
Markus Enders
Keyword(s):  
Ethylene Polymerization ◽  
Weight Control ◽  
Transfer Reactions ◽  
High Catalytic Activity ◽  
Co Catalyst ◽  
Metal Centers ◽  
Molecular Weights ◽  
Metal Interactions ◽  
Polymerization Catalysis ◽  
Very High

A series of Cr(III) complexes based on quinoline-cyclopentadienyl ligands with additional hemilabile side arms were prepared and used as single-site catalyst precursors for ethylene polymerization. The additional donor functions interact with the metal centers only after activation with the co-catalyst. Evidence for this comes from DFT-calculations and from the differing behavior of the complexes in ethylene polymerization. All complexes investigated show very high catalytic activity and the additional side arm minimizes chain-transfer reactions, leading to increase of molecular weights of the resulting polymers.

scholarly journals Syntheses, Solid-state Structures and Catalytic Activity of Zinc Carboxylate Complexes in Lactide Polymerization

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1365-1374 ◽  
Author(s):  
Christoph Scheiper ◽  
Christoph Wölper ◽  
Dieter Bläser ◽  
Joachim Roll ◽  
Stephan Schulz
Keyword(s):  
Ring Opening ◽  
Zinc Complex ◽  
X Ray Diffraction ◽  
Polymerization Catalysts ◽  
Co Catalyst ◽  
Carboxylate Complexes ◽  
X Ray ◽  
Carboxylate Groups ◽  
Solid State Structures ◽  
Lactide Polymerization

Abstract Three dinuclear zinc carboxylate complexes [L1-3Zn(μ,η2-O2CPh)]2 (1, 2, 4) containing either the bidentate N,N′-chelating β-diketiminate ligand RNC(Me)C(H)C(Me)NR (R = 2,6-iPr2-C6H3, L1, complex 1), the tridentate O,N,N-chelating ligand OC(Me)C(H)C(Me)NCH2CH2NMe2 (L2, complex 2) or the bis-N,N′-chelating bis-β-diketiminate ligand RNC(Me)C(H)C(Me)NNC(Me)- C(H)C(Me)NR (R = 2,6-iPr2-C6H3, L3, complex 4) were synthesized and characterized including single-crystal X-ray diffraction. Reaction of the neutral bis-β-diketimine (L3(H)2) with two equivalents of ZnMe2 leads to the expected heteroleptic dinuclear zinc complex L3(ZnMe)2 3 in 93% yield. Further reaction with benzoic acid PhCO2H leads to complex 4. Complex 2 forms a rather strong carboxylate-bridged dimer, whereas the carboxylate groups in complexes 1 and 4 act as asymmetrical bridges between both Zn atoms, pointing to the formation of a weakly bonded dimer. The zinc atoms in 1 and 4 are tetrahedrally coordinated, whereas in 2 the coordination number is increased to five due to the coordination of the pendant donor arm. The ring opening polymerization (ROP) of rac-lactide was investigated with the zinc complexes 1-4 and diazabicycloundec-7-ene (DBU) as a co-catalyst. Complexes 2 and 3 are active polymerization catalysts, which in the presence of DBU converted 200 equiv. of rac-lactide into polylactide within 10 min at ambient temperature. The analysis of the crude polymer showed that the lactide polymerization with catalyst 2 occurs via a slightly modified activated-monomer mechanism.

Introducing electron-donating substituents on ligand backbone of α-diimine nickel complex and the effects on catalyst thermal stability in ethylene polymerization

2019 ◽  
Vol 486 ◽  
pp. 704-710 ◽  
Author(s):  
Feng He ◽  
Dan Wang ◽  
Baiyu Jiang ◽  
Zhen Zhang ◽  
Zhenmei Cheng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ethylene Polymerization ◽  
Nickel Complex

Remote dibenzocycloheptyl substitution on a bis(arylimino)pyridyl-iron ethylene polymerization catalyst; enhanced thermal stability and unexpected effects on polymer properties

2021 ◽  
Author(s):  
Liwei Guo ◽  
Wenjuan Zhang ◽  
Furong Cao ◽  
Youshu Jiang ◽  
Randi Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ethylene Polymerization ◽  
Chloride Complexes ◽  
Polymerization Catalyst ◽  
Polymer Properties

Four examples of para-dibenzocycloheptyl-substituted 2,6-bis(arylimino)pyridyl-iron(II) chloride complexes, [2,6-{(2-R1,4-(C15H13),6-R2C6H2)N=CMe}2C5H3N]FeCl2 (R1 = R2 = Me Fe1, Et Fe2, iPr Fe3, R1 = Me, R2 = Et Fe4), have been synthesized and characterized...

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