Olefin Polymerization by Late Transition Metal Complexes-A Root of Ziegler Catalysts Gains New Ground

Mecking, Stefan

doi:10.1002/1521-3773(20010202)40:3<534::aid-anie534>3.0.co;2-c

Cited by 425 publications

(179 citation statements)

References 70 publications

Supporting

Mentioning

175

Contrasting

Unclassified

Order By: Relevance

“…It is a concerted reaction that combines an unsaturated ligand with an adjacent metal-ligand bond to form a product containing a new ligand with the unsaturated group formally inserted into the original covalent metalligand bond (Scheme 1). A variety of unsaturated ligands undergo migratory insertion, including carbon monoxide, carbon dioxide, alkenes, alkynes, ketones, aldehydes, and imines, and migratory insertion is a common step in numerous catalytic reactions, including hydroformylation, [1,2] hydrogenation, [3][4][5] polymerization, [6][7][8][9] hydroarylation, [10][11][12][13][14] difunctionalization of alkenes, [15][16][17][18] and the olefination of aryl halides (commonly termed the Mizoroki-Heck reaction). [19][20][21][22] In most cases, the unsaturated ligand inserts into a metalcarbon (M À C) or metal-hydrogen (M À H) bond.…”

Section: Introductionmentioning

confidence: 99%

Iridium-Catalyzed, Intermolecular Hydroetherification of Unactivated Aliphatic Alkenes with Phenols

Sevov

Hartwig

2013

J. Am. Chem. Soc.

View full text Add to dashboard Cite

Metal-catalyzed addition of an O−H bond to an alkene is a desirable process because it allows for rapid access to ethers from abundant starting materials without the formation of waste, without rearrangements, and with the possibility to control the stereoselectivity. We report the intermolecular, metal-catalyzed addition of phenols to unactivated α-olefins. Mechanistic studies of this rare catalytic reaction revealed a dynamic mixture of resting states that undergo O−H bond oxidative addition and subsequent olefin insertion to form ether products.

show abstract

Section: Introductionmentioning

confidence: 99%

Iridium-Catalyzed, Intermolecular Hydroetherification of Unactivated Aliphatic Alkenes with Phenols

Sevov

Hartwig

2013

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Their comparatively low oxophilicity has made late transitionmetals attractive candidates in the search for single site catalyst for olefin polymerization [1][2][3]45] that are highly reactive but also tolerant toward polar functional groups and ubiquitous impurities such as water. [4][5][6] Neutral alkyl complexes of Ni stabilized by j 2 -O,N-salicylaldiminato ligands are of particular interest in this context in light of their remarkable functional group tolerance.…”

Section: Introductionmentioning

confidence: 99%

Small changes—Huge influences: NMR chemical shifts of Ni(II) complexes with polar substrates

Frank

Berkefeld

Drexler

et al. 2013

Int J of Quantum Chemistry

View full text Add to dashboard Cite

Neutral Ni(II) complexes have been shown to be highly valuable as robust and versatile catalysts in olefin polymerization. But they show reduced reactivity when the polar monomers methyl acrylate and vinyl acetate are incorporated. To get further insight into this behavior, NMR chemical shift calculations were performed on the system [(N,O) Ni (H) (PMe3)] 1 (N,O = $\kappa ^2$‐N,O‐{2,6‐(3,5‐(F3C)2C6H3)2C6H3)NC(H)‐3,5‐I2‐2‐O‐C6H2}). The chemical shifts show reasonable agreement with experiment but are also extremely influenced by geometrical features of the complex as well as the inserted substrate. The first prominent feature, the low‐field shift of the Ccarbonyl in the incorporated monomer, can only be reproduced when it is in close proximity to the Ni and in this way hinders the attack of a new monomer. Second, the almost 100 ppm difference in the chemical shift of the carbon of the two substrates directly bound to Ni can be reasoned by the different directionality of polarization as disclosed by natural bond orbital (NBO) analysis. © 2013 Wiley Periodicals, Inc.

show abstract

“…There has been increasing interest in the discovery and development of non-cyclopentadienyl transition metal catalysts using titanium, zirconium, iron, nickel, and palladium for ethylene polymerization. [1][2][3][4] As for chromium as a transition metal, cyclopentadienyl complexes are well known for ethylene polymerization. [5][6][7][8][9][10][11][12] Recently, non-cyclopentadienyl chromium catalysts have been reported.…”

Section: Introductionmentioning

confidence: 99%

Ethylene Polymerization with Silica-Supported Cr[N(SiMe3)2]3/Alumoxane Catalyst

Monoi¹,

Ikeda²,

Ohira³

et al. 2002

Polym J

View full text Add to dashboard Cite

ABSTRACT:A new silica-supported non-cyclopentadienyl chromium catalyst having high activity for ethylene polymerization is presented. The catalyst was prepared by supporting tris[bis(trimethylsilyl)amido]chromium(III) Cr[N(SiMe 3 ) 2 ] 3 and alumoxane on silica. The best activity was attained by supporting Cr[N(SiMe 3 ) 2 ] 3 (0.2 wt%-Cr for silica) on silica calcined at 350• C and next supporting a modified-methylalumoxane (Al/Cr molar ratio = 20). Activity during the slurry-phase polymerization was 75100 g-PE/mmol-Cr·hr at 103• C and 1.4 MPa ethylene partial pressure in isobutane. The obtained polyethylene had a relatively high molecular weight and broad molecular weight distribution (HLMFR = 15.6 g/10 min, M w = 330000, M w /M n = 33.0). The calcination temperature of silica had significant influence on the catalyst performance. As calcination temperature increased, short branches, mainly n-butyl and some ethyl branches, were introduced into the resulting polyethylene. There has been increasing interest in the discovery and development of non-cyclopentadienyl transition metal catalysts using titanium, zirconium, iron, nickel, and palladium for ethylene polymerization. [1][2][3][4] As for chromium as a transition metal, cyclopentadienyl complexes are well known for ethylene polymerization. [5][6][7][8][9][10][11][12] Recently, non-cyclopentadienyl chromium catalysts have been reported. [13][14][15][16][17][18][19][20][21][22] These homogeneous catalysts have moderate to high activity depending on the ligand structures. We have been exploring noncyclopentadienyl chromium catalysts because different characteristics could be expected for chromium as a group 6 element from the group 4 elements like titanium and zirconium, the group 8 element like iron and group 10 elements like nickel and palladium. We present a new heterogeneous non-cyclopentadienyl chromium catalyst having high activity for ethylene polymerization with unique features by supporting the tris[bis(trimethylsilyl)amido]chromium(III) complex Cr[N(SiMe 3 ) 2 ] 3 as a transition metal component and alumoxane as an organometallic component on silica. The characteristics of this catalyst influence polymerization activity and polymer structure (molecular weight, molecular weight distribution, and chain branching). The polymerization mechanism is discussed.

show abstract

Olefin Polymerization by Late Transition Metal Complexes-A Root of Ziegler Catalysts Gains New Ground

Abstract: Functional group tolerance and accessibility of unique microstructures are attractive features of olefin polymerization by late transition metal catalysts. Recent discovery of several new classes of highly active catalysts provide access to a range of new materials.

Cited by 425 publications

References 70 publications

Iridium-Catalyzed, Intermolecular Hydroetherification of Unactivated Aliphatic Alkenes with Phenols

Iridium-Catalyzed, Intermolecular Hydroetherification of Unactivated Aliphatic Alkenes with Phenols

Small changes—Huge influences: NMR chemical shifts of Ni(II) complexes with polar substrates

Ethylene Polymerization with Silica-Supported Cr[N(SiMe3)2]3/Alumoxane Catalyst

Contact Info

Product

Resources

About