Copolymerization Of Norbornene Research Articles

Synthesis of 6,13-dihydro-6,13-ethanopentacene-15,16-diimine palladium(II) complex and steric effect of the backbone polycyclic aromatic system on palladium-catalyzed olefin polymerization

The synthesis and characterization of a novel 6,13-dihydro-6,13-ethanopentacene-15,16-diimine palladium(II) complex are described. The effect of the backbone framework of the α-diimine metal catalyst on the polymerization reaction of norbornene and 1-octene is investigated. Compared to the 9,10-dihydro-9,10-ethanoanthracene-11,12-diimine palladium(II) complex (C1), the 6,13-dihydro-6,13-ethanopentacene-15,16-diimine palladium(II) complex (C2) with a polycyclic aromatic system on the backbone exhibits relatively high activities and leads to high molecular weights as well as narrow molecular weight distributions depending on the variation in feed ratios for copolymerization of norbornene and 1-octene. Moreover, the copolymers obtained using the 6,13-dihydro-6,13-ethanopentacene-15,16-diimine palladium(II) complex (C2) with large steric hindrance show high thermal stability and high glass transition temperatures.

Cyclododecene in Olefin Metathesis: Polymerization and Macromolecular Cross-Metathesis with Polynorbornene

The reaction of macromolecular cross-metathesis of polynorbornene and polydodecenamer catalyzed by the first-generation Grubbs Ru-carbene complex is studied for the first time. Polydodecenamer with high-molecular-weight characteristics (Mw = 406 × 103, Ð = 2.5) and a yield of 96% is synthesized by the ring-opening metathesis polymerization of cyclododecene mediated by the second-generation Grubbs catalyst. The polymer has a melting temperature of 62–83°C, depending on the content of trans double bonds, and shows poor solubility in organic solvents at room temperature. Its cross-metathesis with polynorbornene at 40°С gives rise to new statistical multiblock copolymers of norbornene and cyclododecene with different degree of blockiness. NMR, GPC, and DSC were used to investigate the effect of reaction conditions on the structure and thermal properties of the copolymers. At the initial step of the reaction, along with a high-molecular-weight peak, the GPC chromatograms exhibit a peak due to the low-molecular-weight fraction (M = (1–2) × 103), suggesting the formation of cyclooligomers. With increasing degree of interchain exchange, the proportion of the oligomeric fraction decreases appreciably. The kinetics of the cross-metathesis of polynorbornene with polydodecenamer and polyoctenamer at 40°С is studied by in situ 1Н NMR spectroscopy and ex situ 13С NMR spectroscopy. The rates of elementary reactions in these blends differ insignificantly, except for the conversion stage of the initial carbenes into polymer ones. The formation rate for carbene [Ru]=polyoctenamer is three times higher than the formation rate for the [Ru]=polydodecenamer carbene. In both cases, the fraction of Ru carbenes attached to norbornene units is extremely small throughout the process.

Copolymerization of Norbornene and Styrene with Anilinonaphthoquinone-Ligated Nickel Complexes.

Poly(norbornene-co-styrene)s were synthesized by the use of anilinonaphthoquinone-ligated nickel complexes [Ni(C10H5O2NAr)(Ph)(PPh3): 1a, Ar = C6H3-2,6-iPr; 1b, Ar = C6H2-2,4,6-Me; 1c, Ar = C6H5] activated with modified methylaluminoxane (MMAO) or B(C6F5)3 in toluene. The effects of the cocatalysts were more significant than those of the nickel complexes, and MMAO gave higher activity than B(C6F5)3. The structural characterizations of the products indicated the formation of statistical norbornene copolymers. An increase of the styrene ratio in feed led to an increase in the incorporated styrene (S) content of the resulting copolymer. The molecular weight of the copolymer decreased with increasing the S ratio in feed at 70 °C. The copolymerization activity, using MMAO as a cocatalyst, decreased with lowering of the temperature from 70 to 0 °C, accompanied by an increase in the molecular weight of the copolymer. The S incorporation up to 59% with Mn of 78,000 was achieved by the 1b-B(C6F5)3 catalytic system. The glass transition temperatures of the norbornene (N)/S copolymers determined by differential scanning calorimetry, decreased from 329 to 128 °C according to the S content.

Efficient Addition Polymerization of Norbornene with Polar Norbornene Derivatives by Neutral Nickel(II) Catalysts

A series of nickel complexes {4a: [(2,6-iPr2C6H3)N=CHC16H12O]Ni(Me)(Py), 4b: [(2,6-iPr2C6H2OCH3)N=CHC16H12O]-Ni(Me)(Py), 4c: [(2,6-iPr2C6H2Cl)N=CHC16H12O]Ni(Me)(Py), and 4d: [(2,6-iPr2C6H2CF3)N=CHC16H12O]Ni(Me)(Py)} based on β-ketiminato ligands bearing various electron-donating or electron-withdrawing substituents on the para-position of the aniline group were synthesized and unambiguously characterized. The X-ray crystallographic analysis showed that complexes 4b and 4d adopted a near-square-planar geometry, and the anilines bearing a para-OMe or −CF3 group were found to situate on the axial position of the metal center. All complexes exhibited high activities up to 1.25 × 107–1.35 × 107 gPNB·molNi−1·h−1 toward norbornene (NBE) addition polymerization (conversion > 91.2% in 2 min) under low loading of B(C6F5)3 (B/Ni = 3) at 30 °C, affording polymers with high molecular weight up to 2.54 × 106–3.18 × 106. Different levels of decrease in catalytic activities could be observed for all catalysts as the reaction temperature increased; 4d bearing a strong electron-withdrawing −CF3 group showed the highest activity at 70 °C, while others exhibited notable decrease in catalytic activity with the raise in reaction temperature. Complexes 4a–4d showed remarkable tolerance to polar groups and could efficiently promote the copolymerization of NBE with its polar derivatives, including NBE bearing small acetate and hydroxyl group, as well as bulky oligomers, yielding copolymers with high functional NBE incorporations. Novel NBE copolymers with high functional comonomer incorporations and improved solubility were obtained in high yields.

Thermo-responsive micelles prepared from brush-like block copolymers of proline- and oligo(lactide)-functionalized norbornenes

Thermo-responsive micelles were prepared from brush-like block copolymers of proline-derived norbornene and macromonomers bearing oligo(lactide) groups. The brush-like polymers with moderate molecular weights were synthesized by the ring-opening metathesis block copolymerization of a proline-functionalized norbornene (1) with norbornene macromonomers bearing oligo(lactide) groups using Umicore M31 as a catalyst. The proline-functionalized polynorbornene [poly(1)] exhibited the lower critical solution temperature (LCST) at 18 °C. Phase separation was reversible on heating and cooling without hysteresis. Poly(1) featured amphiphilic character, it self-assembled to form micelles in water at temperatures below the LCST, and aggregation of micelles was observed above the LCST. The LCST of the block copolymers increased with increasing percentage of the branched oligo(lactide) component, suggesting that the phase transition temperatures are tunable with respect to the monomer composition. The block copolymers self-assembled into micelles below the LCST, and further aggregated into larger particles, presumably due to dehydration at the corona, at temperatures above the LCST. The block copolymers also showed the potential to self-assemble into a variety of shapes determined by the amphiphilic balance of the block components.

Norbornene Copolymers with Acrylates Bearing Norbornane Moieties: Promising Materials for Optoelectronics

The radical copolymerization of norbornene with norbornenyl acrylate or bornyl acrylate has been studied. New copolymers containing norbornane moieties in the side chain were produced. The influence of the reaction conditions on the composition, molecular weight characteristics, and glass transition temperature of the copolymers was studied. It was established that copolymers of norbornene with norbornenyl acrylate or bornyl acrylate have high transparency (95–97%) in the visible region (400–800 nm) and glass transition temperature. They effectively stabilize semiconductor nanoparticles, which allows these new copolymers to be considered as promising materials for optoelectronics.

Homo- and Copolymerization of Norbornene and Its Derivatives

Homo- and Copolymerization of Norbornene and Its Derivatives

Homoand Copolymerization of Norbornene and its Derivatives

Homoand Copolymerization of Norbornene and its Derivatives

C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands prepared by different in situ bonding mechanisms and their use in catalytic (co)polymerization of norbornene and styrene

Two C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups (─CF3), Ni{PhC(O)CHC[N(9‐fluorenyl)]CF2}2 (Ni1) and Ni{CF3C(O)CHC[N(9‐fluorenyl)]Ph}2 (Ni2), were synthesized by metal coordination reaction and different in situ bonding mechanisms. The C–C bridged bonds of Ni1 were formed by in situ intramolecular trifluoromethyl and 9‐fluorenyl carbon–carbon cross‐coupling reaction and those of Ni2 were formed by in situ intramolecular 9‐fluorenyl carbon–carbon radical coupling reaction mechanism. The obtained complexes were characterized using 1H NMR spectroscopy and elemental analyses. The crystal and molecular structures of Ni1 and Ni2 with C–C bridged configuration were determined using X‐ray diffraction. Ni1 and Ni2 were used as catalysts for norbornene (NB) polymerization after activation with B(C6F5)3 and the catalytic activities reached 106 gpolymer molNi−1 h−1. The copolymerization of NB and styrene catalyzed by the Ni1/B(C6F5)3 system showed high activity (105 gpolymer molNi−1 h−1) and the catalytic activities decreased with increasing feed content of styrene. All vinyl‐type copolymers exhibited high molecular weight (104 g mol−1), narrow molecular weight distribution (Mw/Mn = 1.71–2.80), high styrene insertion ratios (11.13–50.81%) and high thermal stability (Td > 380°C) and could be made into thin films with high transparency in the visible region (400–800 nm).

Copolymerization of 1,3-butadiene and norbornene catalyzed by Ni complexes [1

(bpy)NiBr2 catalyzes the copolymerization of butadiene and norbornene (56:44) in the presence of methylaluminoxane at 30 °C. 1H NMR spectrum of the copolymer contains signals of norbornene units and 1,4-butadiene units and shows the molar ratio of the two monomer units to be 56:44. Copolymerization with a higher portion of norbornene monomer catalyzed by (bpy)NiBr2 affords a solid copolymer rich in norbornene unit, whereas the copolymerization with a higher portion of butadiene forms an oily copolymer rich in butadiene unit. Composition of the monomer units of the copolymer in terms of butadiene/norbornene ratio varies from 12:88 to 91:9, depending on the initial ratio of the monomers; this finding is different from the previous results obtained using Ni catalyst.

Neutral Nickel(II) Complexes Bearing Aryloxide Imidazolin-2-imine Ligands for Efficient Copolymerization of Norbornene and Polar Monomers

A series of novel aryloxide imidazolin-2-imine bidentate neutral Ni(II) complexes with different substituents on the imidazolin-2-imine ligand were synthesized and characterized. The complex Ni2 bearing a 2,6-diisopropylphenyl substituent adopted an almost square planar geometry, while the bulkier 2,6-bis(diphenylmethyl)-4-methylphenyl substituent ligated complex Ni3 was obtained in an allyl adduct base-free η3 coordination mode. In the presence of B(C6F5)3, these Ni(II) complexes exhibited remarkably high activity (up to 2.7 × 107 g of PNB (mol of Ni)−1 h–1) and particularly good thermal stability toward the addition polymerization of norbornene. Most importantly, these catalysts were able to promote the direct copolymerization of norbornene with various polar monomers with high activity (∼105 g (mol of Ni)−1 h–1), reasonable comonomer incorporation (0.14–3.08%), and high copolymer molecular weight (Mn up to 2.0 × 105). The strategy of installing a strongly electron donating imidazolin-2-imine ligand on ...

Structurally simple dinuclear nickel catalyzed olefin copolymerization with polar monomers

The introduction of even low amount of polar functional group is important to expand the range of polyolefin properties. The palladium-catalyzed copolymerization of olefins with polar monomers is a valuable method for the direct synthesis of polar functionalized polyolefins, while low-cost nickel-based catalysts for these copolymerizations still have been limited. Here we report a series of mono- and dinuclear nickel complexes based on structurally simple anilinoanthraquinone ligand for the ethylene copolymerization and norbornene copolymerization with polar monomers. The dinickel catalysts exhibit higher activity and polar monomer incorporation than corresponding mononuclear analogue, owing to the electronic cooperativity effects between the two nickel centers through conjugated ligand.

Epoxidation of Multiblock Copolymers of Norbornene and Cyclooctene

The epoxidation of double bonds in random multiblock copolymers of norbornene and cyclooctene is studied for the first time. The initial copolymers with different composition and average block length are synthesized via the cross-metathesis reaction between polynorbornene and polycyclooctene in the presence of the first-generation Grubbs catalyst. New multiblock copolymers containing oxirane fragments in the backbone are obtained with a yield of 85–92% through epoxidation conducted under the action of m-chloroperbenzoic acid in toluene. The kinetics of epoxidation of polynorbornene, polycyclooctene, and their multiblock copolymers in deuterochloroform and deuterobenzene is investigated via the in situ monitoring of transformation of double bonds using 1Н NMR spectroscopy. It is shown that on the whole the modification of cyclooctene units occurs more easily in copolymers than that in the homopolymer. The thermal properties of epoxidized homo- and copolymers are examined. It is found that upon epoxidation the glass-transition temperature and the melting temperature of multiblock copolymers increase by 40–50 and 20–30°С, respectively, wherein the degree of crystallinity and the temperature of melting grow with the length of the cyclooctene block.

Ethylene–co–norbornene copolymerization in the presence of a chain transfer agent

Ethylene (E)-co-norbornene (N) copolymerizations were conducted by using two ansa-metallocenes, isopropyliden(η5-cyclopentadienyl)(η5-indenyl)zirconium dichloride (1) and isopropyliden(η5-3-methylcyclopentadienyl)(η5-fluorenyl)zirconium dichloride (2), activated with dimethylanilinium tetrakis(pentafluorophenyl)borate, in presence of TIBA and variable amounts of Zn(Et)2 as a potential chain transfer agent (CTA). The study evaluated the effect of CTA on microstructure, molecular weight, chain end group and structural, thermal and mechanical properties of poly(E-co-N)s. The analysis of the data revealed that in all copolymerization reactions with metallocenes 1 and 2 in presence of diethyl zinc chain transfer to zinc alkyl occurs along with the typical chain transfers of E-co-N polymerization. The chain transfer to zinc alkyl is more efficient at low N content in copolymers. The two catalysts show different behavior in copolymerization at high N content: molar masses of copolymers produced by 2 are more affected by CTA concentration, that is, the chain shortening with increasing CTA content is greater in copolymers obtained with catalyst 2. The analysis of mechanical properties revealed that CTA affects the polymer chain structure. An increase of CTA caused a change of ductility, rigidity, and mechanical strength; chains produced in presence of Zn(Et)2 are, at least in part, characterized by segments produced as a result of exchange between different metal centers, possibly jointed through ethylene units.

Microstructure of Copolymers of Norbornene Based on Assignments of 13C NMR Spectra: Evolution of a Methodology.

An overview of the methodologies to elucidate the microstructure of copolymers of ethylene and cyclic olefins through 13C Nuclear magnetic resonance (NMR) analysis is given. 13C NMR spectra of these copolymers are quite complex because of the presence of stereogenic carbons in the monomer unit and of the fact that chemical shifts of these copolymers do not obey straightforward additive rules. We illustrate how it is possible to assign 13C NMR spectra of cyclic olefin-based copolymers by selecting the proper tools, which include synthesis of copolymers with different comonomer content and by catalysts with different symmetries, the use of one- or two-dimensional NMR techniques. The consideration of conformational characteristics of copolymer chain, as well as the exploitation of all the peak areas of the spectra by accounting for the stoichoimetric requirements of the copolymer chain and the best fitting of a set of linear equation was obtained. The examples presented include the assignments of the complex spectra of poly(ethylene-co-norbornene (E-co-N), poly(propylene-co-norbornene (P-co-N) copolymers, poly(ethylene-co-4-Me-cyclohexane)s, poly(ethylene-co-1-Me-cyclopentane)s, and poly(E-ter-N-ter-1,4-hexadiene) and the elucidation of their microstructures.

A Methylene-bridged salicylaldiminato tridentate [ONS] binuclear titanium complex for ethylene-norbornene copolymerization

ABSTRACTA binuclear titanium complex Ti2La with methylene-bridged salicylaldiminato tridentate [ONS] ligand bearing octylthio sidearm was synthesized and used for the copolymerization of ethylene and norbornene (E-NB). The complex exhibited activity over 106 g/mol(Ti).h.atm and high degree incorporation of co-monomer (up to 49.9 mol %), affording high-molecular-weight copolymers with narrow molecular weight distribution. The E-NB copolymers produced by Ti2La/MMAO contained NN dyad and NNN triad sequences even at low norbornene feeds, in contrast to the observation of such sequences only at high level of NB incorporation for most other catalyst systems. The monomer reactivity ratios were calculated to be rE = 14.62 and rN = 0.08, of which the rN value was much larger than that from non-metallocene titanium catalyst systems. The catalytic performances of the binuclear complex Ti2La and its mononuclear analogue TiLb were also compared, with the binuclear complex exhibiting higher catalytic activity and NB incorporation ratio due to the binuclear cooperative effect, and producing much higher molecular weight copolymer due to the increased steric hindrance caused by close proximity of two growing chains. To the best of our knowledge, this is one of the few examples of binuclear catalyst for E-NB copolymerization with high activity and efficient incorporation of norbornene.

Crosslinked norbornene copolymer anion exchange membrane for fuel cells

A series of crosslinked anion exchange membranes (AEMs) were prepared through ring-opening metathesis polymerization (ROMP) of tetraalkylammonium-functionalized norbornene derivatives. Dimensional stability and mechanical properties were enhanced by the crosslinker of 2, 2′-(hexane-1,6-diyl) bis(2-methyl-2, 3, 3a, 4, 7, 7a-hexahydro-1H-4, 7-methanoisoindol-2-ium) iodide (b3). The thermal stability, ion exchange capacity (IEC), water uptake, swelling ratio, ion conductivity and mechanic property of the membranes were investigated. The molar ratios of monomer (3aR, 4 S, 7 R, 7aS)− 2-methyl-2-(3-(trimethylammonio)propyl)−2, 3, 3a, 4, 7, 7a-hexahydro-1H-4,7-methanoisoindol-2-ium iodide (a3): norbornene: monomer b3 was 1:6:3, 2:6:2, 3:6:1 in AEM-1, AEM-2, AEM-3. The resultant AEM-3 membrane had an IEC of 2.89 mmol g−1, an ion conductivity of 64.79 mS·cm−1, a water absorption of 12.5% and a tensile strength of 15.18 MPa at 25 °C. The swelling ratio of AEM-1 (the molar ratio of monomer a3: norbornene: monomer b3 was 1:6:3) was 9.28% at 20 °C and 9.92% at 60 °C. The tensile strength of membranes was improved by the crosslinker. A single cell was built with this AEM-3 membrane and the performance was evaluated. A maximum power density of 152 mW cm−2 at 50 °C was demonstrated. The membranes show great promise to serve as membranes for fuel cells due to excellent performances of higher ion conductivity and better dimensional stability.

Homo- and copolymerization of norbornene with tridentate nickel complexes bearing o-aryloxide-N-heterocyclic carbene ligands.

A series of new pincer-type tridentate o-aryloxide-N-heterocyclic carbene nickel complexes Ni1-Ni3 were synthesized, and the molecular structure of Ni3 was confirmed by X-ray crystallography. In comparison with the above tridentate complexes, the bidentate bis(aryloxide-NHC) nickel complex Ni4 was also synthesized. On activation with either Et2AlCl or Me2AlCl, all nickel complexes showed low activity toward norbornene (NB) homopolymerization. Surprisingly, Ni1-Ni3 catalysts exhibited moderate to high activity toward the homopolymerization (up to 3.21 × 106 g PNB (mol of Ni)-1 h-1) and copolymerization of norbornene with 1-octene (up to 1.39 × 105 g polymer (mol of Ni)-1 h-1) with B(C6F5)3 as the cocatalyst even at 100 °C, showing that tridentate nickel catalysts have high thermal stability. Notably, the tridentate Ni1-Ni3 complexes showed better activities than the corresponding bidentate bis(aryloxide-NHC) nickel complex Ni4. The obtained poly(NB-co-1-octene)s were confirmed to be vinyl-addition copolymers, which exhibited high 1-octene insertion ratio (9%-17%), good thermal stability (Td > 400 °C), high molecular weight (up to 105), and narrow molecular weight distribution (PDI ≤ 1.91).

Efficient control of ethylene–norbornene copolymerization behavior of a fluorenylamido-ligated titanium complex: substituent effects of the amido ligand and copolymer properties

Copolymerization behavior of ethylene and norbornene was controlled using a (fluorenyl)(amido)titanium complex bearing a cumyl-amido ligand.

Selective synthesis of highly soluble cyclic olefin copolymers with pendant vinyl groups using 1,5-hexadiene as a comonomer

Copolymerization of norbornene (NB) and 1,5-hexadiene (HD) was performed using a fluorenylamido-ligated titanium catalyst which conducts copolymerization of NB and 1-alkene. The obtained copolymers possessed pendant vinyl groups, of which content was varied from 0 to 9.4% by the initial feed ratio of the monomers. The copolymers were soluble in various solvents even at high conversion (>85%), showing that the crosslinking of pendant vinyl groups was negligible. The glass transition temperature of the copolymer was changed from 79 °C to over 300 °C, depending on the comonomer composition. Post-functionalization of the pendant vinyl groups with 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene via ruthenium-catalyzed metathesis reaction was also performed and fluoroalkyl-functionalized cyclic olefin copolymer was successfully obtained. The fluorinated copolymer film showed higher contact angle than the unfunctionalized copolymer.