Ethylene Polymerization by Palladium/Phosphine–Sulfonate Catalysts in the Presence and Absence of Protic Solvents: Structural and Mechanistic Differences

Kanazawa, Masafumi; Ito, Shingo; Nozaki, Kyoko

doi:10.1021/om2004207

Cited by 15 publications

(14 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to elucidate whether the observed insertion modes found for the Pd–Me catalyst precursor 1‐dmso occur analogously for the Pd–H species formed during polymerization by chain transfer (vide infra), insertion into the isolated complex 1‐H‐P t Bu 3 [19b] was studied. In an NMR tube, 1‐H‐P t Bu 3 (20 × 10 −3 m Pd) was dissolved in a 1.2 m CD 3 OD solution in CD 2 Cl 2 .…”

Section: Resultsmentioning

confidence: 99%

“…In an NMR tube, 1‐H‐P t Bu 3 (20 × 10 −3 m Pd) was dissolved in a 1.2 m CD 3 OD solution in CD 2 Cl 2 . Heating this reaction mixture (80 °C, 2 d) in the presence of diethyl vinyl phosphonate (2 equiv) results in H/D exchange between Pd–H and the CD 3 OD solvent to form Pd–D species, which subsequently insert the vinyl moiety, followed by β‐H/D elimination . This results in a partial deuteration of the vinyl group allowing for conclusions on the insertion modes.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Nanocomposites of Phosphonic‐Acid‐Functionalized Polyethylenes with Inorganic Quantum Dots

Rünzi

Baier

Negele

et al. 2014

Macromol. Rapid Commun.

View full text Add to dashboard Cite

Insertion of diethyl vinyl phosphonates and free vinyl phosphonic acid, respectively, into [(P^O)Pd(Me)(dmso)] ((P^O) = κ(2)-P,O-Ar2PC6H4SO2O with Ar = 2-MeOC6H4) (1-dmso) occurs in a 2,1- as well as 1,2-fashion, to form a four-and a five-membered chelate [(P^O)Pd{κ(2)-C,O-CH(P(O)(OR)2)CH2CH3}] and [(P^O)Pd{κ(2)-C,O-CH2CH(P(O)(OR)2)CH3}] (R = H, Et). No decomposition or other reactions of 1 by free phosphonic acid moieties occur. Copolymerization in a pressure reactor by 1-dmso yields linear random poly(ethylene-co-diethyl vinyl phosphonate) and poly(ethylene-co-vinyl phosphonic acid). In these copolymerizations, reversible coordination of the phosphonate moieties of free monomer as well as chelate formation by incorporated monomer retards chain growth as also evidenced by relative binding studies of diethyl phosphonate towards 1. Post-polymerization emulsification of poly(ethylene-co-vinyl phosphonic acid) together with CdSe/CdS quantum dots (QDs) yields submicron (ca. 50 nm from dynamic light scattering (DLS) and transmission electron microscopy (TEM)) polymer particles with the QDs embedded in the functionalized polyethylene in a nonaggregated fashion. This embedding benefits the fluorescence behavior in terms of continuous emission and life-time as revealed by wide-field fluorescence measurements. These composite particle dispersions are employed as a ″masterbatch" together with an aqueous high density polyethylene (HDPE) dispersion to generate thin films (by spin-coating) and bulk materials (from the melt), respectively, in which the inorganic nanoparticles remain highly disperse.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Nanocomposites of Phosphonic‐Acid‐Functionalized Polyethylenes with Inorganic Quantum Dots

Rünzi

Baier

Negele

et al. 2014

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

“…In fact, even for cases of thylene polymerization to a strictly linear polymer, extensive underlying chain walking occurs. [16][17][18] Scheme 1. Synthetic relevance of chain walking processes: oligomerization of ethylene to hyperbranched oligomers.…”

Section: Introductionmentioning

confidence: 99%

Control of Chain Walking by Weak Neighboring Group Interactions in Unsymmetrical Catalysts

et al. 2018

View full text Add to dashboard Cite

A combined theoretical and experimental study shows how weak attractive interactions of a neighboring group can strongly promote chain walking and chain transfer. This accounts for the previously observed very different microstructures obtained in ethylene polymerization by [κ-N,O-{2,6-(3',5'-RCH)CH-N═C(H)-(3,5-X,Y-2-O-CH)}NiCH(pyridine)], namely hyperbranched oligomers for remote substituents R = CH versus high-molecular-weight polyethylene for R = CF. From a full mechanistic consideration, the alkyl olefin complex with the growing chain cis to the salicylaldiminato oxygen donor is identified as the key species. Alternative to ethylene chain growth by insertion in this species, decoordination of the monomer to form a cis β-agostic complex provides an entry into branching and chain-transfer pathways. This release of monomer is promoted and made competitive by a weak η-coordination of the distal aryl rings to the metal center, operative only for the case of sufficiently electron-rich aryls. This concept for controlling chain walking is underlined by catalysts with other weakly coordinating furan and thiophene motifs, which afford highly branched oligomers with >120 branches per 1000 carbon atoms.

show abstract

“…The resulting latex was dark‐colored (Figure S4), indicating catalyst decomposition and a low amount of polymer. Such a low rate is expected, as water has been reported to deactivate late transition metal polymerization catalysts, mostly in a reversible manner by σ coordination to the Pd atom, and also by irreversible hydrolysis of the Pd−C bond . Thus, under similar conditions, the activity in an aqueous environment was three orders of magnitude lower than that in an organic solvent.…”

Section: Figurementioning

confidence: 94%

Water and Carbon Dioxide: A Unique Solvent for the Catalytic Polymerization of Ethylene in Miniemulsion

Daigle

Lucien

Zetterlund

et al. 2017

Chemistry An Asian Journal

View full text Add to dashboard Cite

The catalytic polymerization of ethylene is performed in water pressurized with CO . The size of the initial monomer droplets and of the resulting polymer particles can be varied by simply changing the CO pressure. Furthermore, at identical ethylene partial pressure, the polymerizations performed in the presence of CO are significantly faster than in its absence. Thus, the combination of CO and water is a promising green solvent for catalytic emulsion polymerizations.

show abstract

Ethylene Polymerization by Palladium/Phosphine–Sulfonate Catalysts in the Presence and Absence of Protic Solvents: Structural and Mechanistic Differences

Cited by 15 publications

References 43 publications

Nanocomposites of Phosphonic‐Acid‐Functionalized Polyethylenes with Inorganic Quantum Dots

Nanocomposites of Phosphonic‐Acid‐Functionalized Polyethylenes with Inorganic Quantum Dots

Control of Chain Walking by Weak Neighboring Group Interactions in Unsymmetrical Catalysts

Water and Carbon Dioxide: A Unique Solvent for the Catalytic Polymerization of Ethylene in Miniemulsion

Contact Info

Product

Resources

About