Heterobimetallic [Ti, Al] Complexes: Divergent Synthesis, Redox Properties, and Ethylene Polymerization Catalysis

2021 ◽  
Author(s):  
Amit Kumar ◽  
Jared L. Barr ◽  
Carlos A. Cruz ◽  
James D. Blakemore
Keyword(s):  
Ethylene Polymerization ◽  
Redox Properties ◽  
Polymerization Catalysis

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.

Ethylene Polymerization Catalysis by Vanadium-Based Systems Bearing Sulfur-Bridged Calixarenes

2011 ◽  
Vol 30 (21) ◽  
pp. 5620-5624 ◽  
Author(s):  
Carl Redshaw ◽  
Lucy Clowes ◽  
David L. Hughes ◽  
Mark R. J. Elsegood ◽  
Takehiko Yamato
Keyword(s):  
Ethylene Polymerization ◽  
Polymerization Catalysis

2,6-Diiminopyridine Iron(II) Dialkyl Complexes. Interaction with Aluminum Alkyls and Ethylene Polymerization Catalysis

2005 ◽  
Vol 24 (21) ◽  
pp. 4878-4881 ◽  
Author(s):  
Juan Cámpora ◽  
A. Marcos Naz ◽  
Pilar Palma ◽  
Eleuterio Álvarez ◽  
Manuel L. Reyes
Keyword(s):  
Ethylene Polymerization ◽  
Polymerization Catalysis ◽  
Aluminum Alkyls

Synthesis, mechanism and ethylene polymerization catalysis of Ge(iv), Sn(ii) and Zr(iv) complexes derived from substituted β-diketiminates

RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 60723-60728 ◽  
Author(s):  
Xia Xiao ◽  
Xiaomin Hao ◽  
Jianliang Bai ◽  
Jianbin Chao ◽  
Wei Cao ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Elimination Reaction ◽  
Synthesis Mechanism ◽  
X Ray ◽  
Polymerization Catalysis

Unusual X-ray characterized crystalline Sn(ii), Ge(iv) and Zr(iv) complexes have been prepared via a salt metathesis and elimination reaction.

Rare Earth Metal Alkyl Complexes with Methyl-Substituted Triazacyclononane-amide Ligands:  Ligand Variation and Ethylene Polymerization Catalysis

2007 ◽  
Vol 26 (4) ◽  
pp. 1014-1023 ◽  
Author(s):  
Sergio Bambirra ◽  
Daan van Leusen ◽  
Cornelis G. J. Tazelaar ◽  
Auke Meetsma ◽  
Bart Hessen
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Ethylene Polymerization ◽  
Earth Metal ◽  
Alkyl Complexes ◽  
Amide Ligands ◽  
Polymerization Catalysis

Ethylene and 1-hexene polymerization using zirconium iminophosphonamide complexes

2006 ◽  
Vol 84 (2) ◽  
pp. 214-224 ◽  
Author(s):  
Robert Tomaszewski ◽  
Rainer Vollmerhaus ◽  
Abdulaziz Al-Humydi ◽  
Qinyan Wang ◽  
Nicholas J Taylor ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Room Temperature ◽  
Chain Transfer ◽  
Single Site ◽  
Complex Behavior ◽  
Polymerization Catalysts ◽  
Dichloromethane Solution ◽  
Polymerization Catalysis ◽  
Multinuclear Nmr Spectroscopy ◽  
Poly Ethylene

Ethylene polymerization was studied using a variety of iminophosphonamide (PN2) complexes of zirconium. Bis(PN2) dichloride complexes [Ph2P(NR′)2]2ZrX2 (X = Cl; 1a: R′ = p-tolyl; 1b: R′ = Bn; 1c: R′ = C6F5) or dimethyl complexes (X = Me; 2a: R′ = p-tolyl; 2b: R′ = Bn) and cyclopentadienyl(PN2)zirconium dichloride complexes [η5-C5R′′5][R2P(NR′)2]ZrCl2 (3a: R′ = p-tolyl, R = Ph, R′′ = H; 3b: R′ = SiMe3, R = Et, R′′ = H; 3c: R′ = C6F5, R = Ph, R′′ = H; 3e: R′ = 3,5-(CF3)2Ph, R = Ph, R′′ = H; 3f: R′ = 3,5-(CF3)2Ph, R = Ph, R′′ = Me) or dimethyl analogs [η5-C5H5][R2P(NR′)2]ZrMe2 (4a: R′ = p-tolyl, R = Ph; 4b: R′ = SiMe3, R = Et) were evaluated under a range of conditions using methylaluminoxane (PMAO) activator. Complexes 1 and 2 behave as precursors to single-site polymerization catalysts under the conditions studied, while complexes 3 or dialkyls 4 show more complex behavior and formation of poly(ethylene) with a bimodal molecular weight distribution. In contrast, activation of dialkyl complexes 4 with [Ph3C][B(C6F5)4] and polymerization in the presence of small amounts of PMAO or TIBAL as scavenger, led to single-site behavior. PMAO reacts with the neutral dialkyls via ligand abstraction to produce a number of P-containing species that may explain the multi-site behavior observed when using this activator. Dialkyls 4 react cleanly with [Ph3C][B(C6F5)4] in haloarene or even dichloromethane solution to furnish the corresponding cationic alkyls 5, which were characterized by multinuclear NMR spectroscopy. Fluxional dinuclear species are formed in the presence of excess dialkyl and these are susceptible to C—H activation to form µ-Me,µ-CH2 complexes one of which could be isolated in pure form. The cationic alkyls initiate the polymerization of 1-hexene at room temperature in chlorobenzene solution, but extensive chain transfer occurs and the systems are not living.Key words: single site, early metal olefin polymerization catalysis.

Titanium pyridyl-phosphinimide complexes — Synthesis, structure, and ethylene polymerization catalysis

2006 ◽  
Vol 84 (5) ◽  
pp. 755-761 ◽  
Author(s):  
Chad Beddie ◽  
Pingrong Wei ◽  
Douglas W Stephan
Keyword(s):  
Molecular Weight ◽  
Key Words ◽  
Ethylene Polymerization ◽  
Olefin Polymerization ◽  
Polymerization Catalysts ◽  
Pyridyl Group ◽  
Molecular Weight Distributions ◽  
Polymerization Catalysis ◽  
Weight Distributions

A series of Ti–pyridyl-phosphinimide complexes of the form Cp′TiX2[NPR2(2-CH2Py)] (Cp′ = Cp, Cp*, R = i-Pr, t-Bu, X = Cl, Me) have been prepared and characterized. These complexes generate ethylene polymerization catalysts upon activation with MAO or B(C6F5)3. The resulting polymers exhibit broad molecular weight distributions. The role of the pyridyl group is discussed in light of stoichiometric reactions of CpTiCl2[NPR2(2-CH2Py)] with B(C6F5)3.Key words: phosphinimide complexes, pyridyl-phosphinimides, olefin polymerization.

Zirconium Phosphinimide Complexes:  Synthesis, Structure, and Deactivation Pathways in Ethylene Polymerization Catalysis

2001 ◽  
Vol 20 (21) ◽  
pp. 4424-4433 ◽  
Author(s):  
Nancy Yue ◽  
Emily Hollink ◽  
Fred Guérin ◽  
Douglas W. Stephan
Keyword(s):  
Ethylene Polymerization ◽  
Polymerization Catalysis

scholarly journals Bis(η5-cyclopentadienyl)bistriphenylsilanolatozirconium( IV): a new precursor for ethylene polymerization catalysis

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Angelina Altomare ◽  
Roberta Candian ◽  
Marco Michelotti ◽  
Guido Pampaloni ◽  
Francesco Ciardelli
Keyword(s):  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Catalytic Performance ◽  
Ligand Substitution ◽  
Polymerization Catalysis ◽  
Comparable Activity

AbstractTrialkylsilanols were reported to modify and also to improve the catalytic performance in ethylene polymerization when added to zirconocene/methylaluminoxane (MAO) systems. In order to obtain more information about the chemistry involved, a new stable catalytic precursor was investigated in this work. The precursor bis(h5-cyclopentadienyl)bistriphenylsilanolatozirconium(IV) [ZrCp2(OSiPh3)2] was compared to ZrCp2(CH3)2 and ZrCp4, which can generate ZrCp2(OSiPh3)2 in situ on triphenylsilanol addition. In ethylene polymerization, ZrCp2(OSiPh3)2 exibits a comparable activity and a larger stability than dicyclopentadienylzirconium complexes. On addition of triphenylsilanol to zirconocenes, the productivity increased and the molecular weight sharply decreased, thus suggesting the occurrence of ligand substitution in solution. The reported results are discussed with reference to the proposed mechanism of ethylene polymerization with the conventional ZrCp2Cl2/MAO system.

Sign in / Sign up

Export Citation Format

Share Document