<i>Organometallics</i> Roundtable 2011

Gladysz, J. A.; Ball, Zachary T.; Bertrand, Guy; Blum, Suzanne A.; Dong, Vy M.; Dorta, Reto; Hahn, F. Ekkehardt; Humphrey, Mark G.; Jones, William D.; Klosin, Jerzy; Manners, Ian; Marks, Tobin J.; Mayer, James M.; Rieger, Bernhard; Ritter, Joachim; Sattelberger, Alfred P.; Schomaker, Jennifer M.; Yam, Vww

doi:10.1021/om201234x

Cited by 33 publications

(26 citation statements)

References 31 publications

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“…[7] Thedevelopment of novel catalyst systems that can tolerate polar functional groups is the key.Amilestone discovery was made by Brookhart and co-workers in the 1990s (Scheme 1, catalyst A), who demonstrated the a-diimine-Pd II catalyzed copolymerization of ethylene (E) with methyl acrylate (MA). [7] Thedevelopment of novel catalyst systems that can tolerate polar functional groups is the key.Amilestone discovery was made by Brookhart and co-workers in the 1990s (Scheme 1, catalyst A), who demonstrated the a-diimine-Pd II catalyzed copolymerization of ethylene (E) with methyl acrylate (MA).…”

Section: Shengyu Dai and Changle Chen*mentioning

confidence: 99%

Direct Synthesis of Functionalized High‐Molecular‐Weight Polyethylene by Copolymerization of Ethylene with Polar Monomers

2016

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The introduction of even a small amount of polar functional groups into polyolefins could excise great control over important material properties. As the most direct and economic strategy, the transition-metal-catalyzed copolymerization of olefins with polar, functionalized monomers represents one of the biggest challenges in this field. The presence of polar monomers usually dramatically reduces the catalytic activity and copolymer molecular weight (to the level of thousands or even hundreds Da), rendering the copolymerization process and the copolymer materials far from ideal for industrial applications. In this contribution, we demonstrate that these obstacles can be addressed through rational catalyst design. Copolymers with highly linear microstructures, high melting temperatures, and very high molecular weights (close to or above 1 000 000 Da) were generated. The direct synthesis of polar functionalized high-molecular-weight polyethylene was thus achieved.

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Section: Shengyu Dai and Changle Chen*mentioning

confidence: 99%

Direct Synthesis of Functionalized High‐Molecular‐Weight Polyethylene by Copolymerization of Ethylene with Polar Monomers

2016

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“…The catalytic polymerization of alkenes such as ethylene or propylene is among the synthetic reactions performed on the largest scale today. By contrast, the insertion copolymerization of ethylene with polar vinyl monomers for the direct synthesis of functionalized polyolefins has been recognized as one of the major unsolved problems in the polymer field . Polymers that bear polar functional groups are highly desirable materials because of their unique properties: compared to their nonfunctionalized analogues, they exhibit advantageous surface properties with respect to adhesion, toughness, printability, paintability, and compatibility with other materials .…”

Section: Introductionmentioning

confidence: 99%

Palladium‐Catalyzed Ethylene/Methyl Acrylate Co‐Oligomerization: The Effect of a New Nonsymmetrical α‐Diimine with the 1,4‐Diazabutadiene Skeleton

et al. 2017

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PdII complexes with a nonsymmetrical bis(aryl‐imino)diazabutadiene ligand (ArDAB) have been synthesized and characterized. The new ligand features one aryl ring substituted in the ortho positions with a methyl group and the other ring that bears a trifluoromethyl group on the meta positions, which leads to subtle steric and electronic differences at the two N donor atoms. This peculiar substitution makes the direct synthesis of the ligand unfeasible, and the relevant PdII complex, [Pd(CH3)Cl(ArDAB)], is obtained directly through a template reaction. The corresponding cationic complexes with either acetonitrile or DMSO were synthesized and characterized. The X‐ray crystal structure of a Pd complex with an α‐diimine and DMSO is reported. The monocationic complexes were tested as precatalysts in ethylene/methyl acrylate co‐oligomerization under mild reaction temperature and pressure conditions. A comparison of the catalytic behavior of the precatalysts with the corresponding nonsymmetrical aryl α‐diimines with an acenaphthene skeleton indicated that the active species with the new ligand is more productive and leads to the formation of ethylene oligomers and ethylene/methyl acrylate co‐oligomers.

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“…More recently, an organometallic uranium complex was shown to effect the simultaneous reduction and hydrogenation of CO to give a coordinated methoxide that could be liberated as CH 3 OSiMe 3 (31); however, there have been no reports of successful homologation, functionalization, and removal of C n -oligomers (n ≥ 2) under mild conditions with retention of a metal complex that may be recycled for reuse in a synthetic cycle as has been demonstrated for CO 2 (32, 33), P 4 (34), and carbodiimides (35). Thus, the direct homologation of carbon monoxide into oxycarbons in viable, simple, and straightforward synthetic cycles is yet to be accomplished (36).…”

mentioning

confidence: 99%

Homologation and functionalization of carbon monoxide by a recyclable uranium complex

Gardner

Stewart

Davis

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

164

110

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Carbon monoxide (CO) is in principle an excellent resource from which to produce industrial hydrocarbon feedstocks as alternatives to crude oil; however, CO has proven remarkably resistant to selective homologation, and the few complexes that can effect this transformation cannot be recycled because liberation of the homologated product destroys the complexes or they are substitutionally inert. Here, we show that under mild conditions a simple triamidoamine uranium(III) complex can reductively homologate CO and be recycled for reuse. Following treatment with organosilyl halides, bis(organosiloxy)acetylenes, which readily convert to furanones, are produced, and this was confirmed by the use of isotopically 13 C-labeled CO. The precursor to the triamido uranium(III) complex is formed concomitantly. These findings establish that, under appropriate conditions, uranium(III) can mediate a complete synthetic cycle for the homologation of CO to higher derivatives. This work may prove useful in spurring wider efforts in CO homologation, and the simplicity of this system suggests that catalytic CO functionalization may soon be within reach.reduction | C-C coupling | ethyne diolate | antiferromagnetic exchange coupling T he continued growth and stability of the global economy requires the ready availability of petrochemical feedstocks, but uncertainty in cost and supply, underscored by the energy crisis in the 1970s, has driven the demand for developing alternative sources (1). CO is readily produced by steam reforming reactions and is, thus, an abundant resource that can be used in the production of bulk hydrocarbon feedstocks (2). The concept of directly homologating CO is very appealing, but the triple bond in CO is very strong with a bond energy of ∼257 kcal mol −1 , and direct dimerization of CO to O ¼ C ¼ C ¼ O is highly unfavorable with ΔG°2 98 K ≈ þ73 kcal mol −1 (3). Although direct 1,1-migratory insertion of CO into an organometallic M-R bond to give M-C(O)R is a favorable process for many metals (4) and a key step in industrially important C-C bond formation reactions, e.g., hydroformylation (5), double insertion to give M-C(O)C(O)R is usually energetically unfeasible, but it has been documented (6-8). Thus, processes involving CO can require energy intensive reaction conditions and give varied product distributions that render them economically uncompetitive overall when crude oil remains readily available; however, combining the coupling of CO with reduction results in a thermodynamically feasible process to give a family of oxocarbon dianions C n O n 2− (n ¼ 2-6), including the reductively dimerized ethyne diolate − O-C ≡ C-O − , as building blocks for more complex and value-added organic molecules (9).Molten potassium can effect reductive oligomerization of CO, but the resulting ill-defined salts are thermally unstable and shock-sensitive (10). CO can be electrochemically homologated, but an overpressure of 100-400 bar of CO is required (11). Very few transition metal complexes mediate the reductive coupling...

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Organometallics Roundtable 2011

Cited by 33 publications

References 31 publications

Direct Synthesis of Functionalized High‐Molecular‐Weight Polyethylene by Copolymerization of Ethylene with Polar Monomers

Direct Synthesis of Functionalized High‐Molecular‐Weight Polyethylene by Copolymerization of Ethylene with Polar Monomers

Palladium‐Catalyzed Ethylene/Methyl Acrylate Co‐Oligomerization: The Effect of a New Nonsymmetrical α‐Diimine with the 1,4‐Diazabutadiene Skeleton

Homologation and functionalization of carbon monoxide by a recyclable uranium complex

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