Copolymerization of Ethylene and 3,3,3-Trifluoropropene Using (Phosphine-sulfonate)Pd(Me)(DMSO) as Catalyst

Mechanistic Study on Steric Activity Interplay of Olefin/Polar Monomers for Industrially Selective Late Transition Metal Catalytic Reactions

A significant issue in developing metal-catalyzed plastic polymer materials is obtaining distinctive catalytic characteristics to compete with current plastics in industrial commodities. We performed first-principle DFT calculations on the key insertion steps for industrially important monomers, vinyl fluoride (VF) and 3,3,3-trifluoropropene (TFP), to explain how the ligand substitution patterns affect the complex's polymerization behaviors. Our results indicate that the favorable 2,1-insertion of TFP is caused by less deformation in the catalyst moiety of the complexes in contrast to the 1,2-insertion mode. In contrast to the VF monomer, the additional interaction between the fluorine atoms of 3,3,3-trifluoropropene and the carbons of the catalyst ligands also contributed to favor the 2,1-insertion. It was found that the regioselectivity of the monomer was predominated by the progressive alteration of the catalytic geometry caused by small dihedral angles that were developed after the ligand-monomer interaction. Based on the distribution of the 1,2- and 2,1-insertion products, the activity and selectivity were influenced by the steric environment surrounding the palladium center; thus, an increased steric bulk visibly improved the selectivity of the bulkier polar monomer (TFP) during the copolymerization mechanism. In contrast, better activity was maintained through a sterically less hindered Pd metal center; the calculated moderate energy barriers showed that a catalyst with less steric hindrance might provide an opportunity for a wide range of prospective industrial applications.

Custom-made polar monomers utilized in nickel and palladium promoted olefin copolymerization

In this review, the functions of custom-made polar monomers are insightfully emphasized in the preparation of functional polyolefins.

Palladium-Catalyzed Insertion of Ethylene and 1,1-Disubstituted Difunctional Olefins: An Experimental and Computational Study

Insertion or coordination copolymerization of ethylene with di-substituted olefins is challenging and the choice of di-substituted mono-functional olefin versus di-substituted di-functional olefin (DDO) appears to be decisive. Here we show that DDO-inserted species are amenable to ethylene insertion and polymerization. DDOs such as 2-acetamidoacrylic acid (AAA), methyl 2-acetamidoacrylate (MAAA), and ethyl 2-cyanoacrylate (ECA) were treated with palladium complex [{P∧O}PdMe(L)] (P∧O=κ² -P,O-Ar₂ PC₆ H₄ SO₂ O with Ar=2-MeOC₆ H₄ ; L=C₂ H₆ OS) and the existence of respective insertion intermediates in moderate yield (up to 37 %) was established. These intermediates were exposed to ethylene and corresponding ethylene-inserted products were isolated and characterized. A careful comparison with three model compounds confirmed ethylene insertion and polymerization. Thus, the combined experimental and computational investigations show that DDO-inserted species can undergo ethylene insertion and polymerization.

Ligand–metal secondary interactions in phosphine–sulfonate palladium and nickel catalyzed ethylene (co)polymerization

Ligand secondary interactions and Lewis acid modulation are simultaneously achieved in palladium and nickel catalyzed ethylene polymerization and copolymerization.

Synthesis of fluorinated polyethylene of different topologies via insertion polymerization with semifluorinated acrylates

Fluorinated polyethylene with different topologies can be generated via insertion polymerization with various late-transition-metal catalysts.

Sterically very bulky aliphatic/aromatic phosphine-sulfonate palladium catalysts for ethylene polymerization and copolymerization with polar monomers

Copolymerization of ethylene and polar monomers with significantly high molecular weight and activity was achieved using bulky aliphatic/aromatic phosphine-sulfonate palladium catalysts.

An efficient and mild route to highly fluorinated polyolefins via copolymerization of ethylene and 5-perfluoroalkylnorbornenes

Highly efficient copolymerization of ethylene/5-(perfluoro-n-alkyl)norbornenes has been realized for the synthesis of fluorinated COC for the first time.

Coordination–insertion polymerization of polar allylbenzene monomers

Utilization of polar allylbenzene allows for a much enhanced activity (9–6300 times) of polar allyl monomers in the coordination–insertion copolymerization.

Methylene-Bridged Bisphosphine Monoxide Ligands for Palladium-Catalyzed Copolymerization of Ethylene and Polar Monomers

A series of palladium complexes bearing a bisphosphine monoxide with a methylene linker, that is, [κ²-P,O-(R¹₂P)CH₂P(O)R²₂]PdMe(2,6-lutidine)][BAr^F₄] (Pd/BPMO), were synthesized and evaluated as catalysts for the homopolymerization of ethylene and the copolymerization of ethylene and polar monomers. X-ray crystallographic analyses revealed that these Pd/BPMO complexes exhibit significantly narrower bite angles and longer Pd-O bonds than Pd/BPMO complexes bearing a phenylene linker, while maintaining almost constant Pd-P bond lengths. Among the complexes synthesized, menthyl-substituted complex 3f (R¹ = (1R,2S,5R)-2-isopropyl-5-methylcyclohexan-1-yl; R² = Me) showed the best catalytic performance in the homo- and copolymerization in terms of molecular weight and polymerization activity. Meanwhile, complex 3e (R¹ = t-Bu; R² = Me) exhibited a markedly higher incorporation of comonomers in the copolymerization of ethylene and allyl acetate (≤12.0 mol %) or methyl methacrylate (≤0.6 mol %). The catalytic system represents one of the first examples of late-transition-metal complexes bearing an alkylene-bridged bidentate ligand that afford high-molecular-weight copolymers from the copolymerization of ethylene and polar monomers.

Organometallic-Mediated Radical Polymerization of Vinylidene Fluoride

An unprecedented level of control for the radical polymerization of vinylidene fluoride (VDF), yielding well-defined PVDF (at least up to 14 500 g mol^-1 ) with low dispersity (≤1.32), was achieved using organometallic-mediated radical polymerization (OMRP) with an organocobalt compound as initiator. The high chain-end fidelity was demonstrated by the synthesis of PVDF- and PVAc-containing di-and triblock copolymers. DFT calculations rationalize the efficient reactivation of both head and tail chain end dormant species.

Olefin Insertion into a Pd-F Bond: Catalyst Reactivation Following β-F Elimination in Ethylene/Vinyl Fluoride Copolymerization

The discrete (phosphinoarenesulfonate)Pd fluoride complex (PO^Bp,OMe )PdF(lutidine), where PO^Bp,OMe =(2-MeOC₆ H₄ )(2-{2,6-(MeO)₂ C₆ H₃ }C₆ H₄ )(2-SO₃ -5-MeC₆ H₃ )P, inserts vinyl fluoride (VF) to form (PO^Bp,OMe )PdCH₂ CHF₂ (lutidine) and inserts multiple ethylene (E) units to generate polyethylene that contains -CH₂ F chain ends. These results provide strong evidence that the -CHF₂ and -CH₂ F chain ends in E/VF copolymer generated by (phosphinoarenesulfonate)PdR catalysts form by β-F elimination of Pd(β-F-alkyl) species, VF or E insertion of the resulting (PO)PdF species, and subsequent chain growth. These results also imply that β-F elimination is not an important catalyst deactivation reaction in this system.

Manipulation of polymer branching density in phosphine-sulfonate palladium and nickel catalyzed ethylene polymerization

A series of palladium and nickel catalysts bearing heteroaryl-aryl moieties were prepared and applied to ethylene polymerization and copolymerization reactions.

Copolymerisation of ethylene with polar monomers by using palladium catalysts bearing an N-heterocyclic carbene–phosphine oxide bidentate ligand

We report the synthesis and characterisation of palladium complexes bearing an N-heterocyclic carbene–phosphine oxide bidentate ligand and their use as catalysts for ethylene polymerisation and ethylene/polar monomer copolymerisation.

Insertion Homo- and Copolymerization of Diallyl Ether

The previously unresolved issue of polymerization of allyl monomers CH2 CHCH2 X is overcome by a palladium-catalyzed insertion polymerization of diallyl ether as a monomer. An enhanced 2,1-insertion of diallyl ether as compared to mono-allyl ether retards the formation of an unreactive five-membered cyclic O-chelate (after 1,2-insertion) that otherwise hinders further polymerization, and also enhances incorporation in ethylene polymers (20.4 mol %). Cyclic ether repeat units are formed selectively (96 %-99 %) by an intramolecular insertion of the second allyl moiety of the monomer. These features even enable a homopolymerization to yield polymers (poly-diallyl ether) with degrees of polymerization of DPn ≈44.

Insertion Copolymerization of Difunctional Polar Vinyl Monomers with Ethylene

A single-step synthesis, structural characterization and application of a neutral, acetonitrile ligated, palladium-phosphinesulfonate complex [{P^∧O}PdMe(L)] (P^∧O = κ²-P,O-Ar₂PC₆H₄SO₂O with Ar = 2-MeOC₆H₄; L = CH₃CN) (3) in coordination/insertion copolymerization of ethylene with difunctional olefin is investigated. In a significant development, complex 3 was found to catalyze insertion copolymerization of industrially relevant 1,1-disubstituted difunctional vinyl monomers for the first time. Thus, insertion copolymerization of ethyl-2-cyanoacrylate (ECA or super glue) and trifluoromethyl acrylic acid (TFMAA) with ethylene produced the corresponding copolymers with 6.5% ECA and 3% TFMAA incorporation. Increasing the concentration of difunctional olefins led to higher incorporation but at the expense of lower activities. These observations indicate that complex 3 tolerates difunctional vinyl monomers and provides direct access to difunctional polyolefins that have not been attempted before.