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Showing papers on "Norbornene published in 2022"


Journal ArticleDOI
TL;DR: In this paper , three fluorinated ladder diamines with norbornyl benzocyclobutene (N2BC) segments were prepared by catalytic norbornene-arene annulation (CANAL) reactions of norbornadiene with fluorinated bromoanilines.
Abstract: Three fluorinated ladder diamines with norbornyl benzocyclobutene (N2BC) segments were prepared by catalytic norbornene-arene annulation (CANAL) reactions of norbornadiene with fluorinated bromoanilines. NMR results revealed that two regioisomers were obtained for each diamine, with syn-to-anti ratios of ∼2:1. High-temperature solution polycondensation of these diamines with commercial dianhydrides produced a series of colorless polyimides (CPIs). These polymers exhibited extremely high glass-transition temperatures (Tg) of 390–479 °C, reasonable coefficients of thermal expansion of 36–61 ppm K–1, and excellent optical transparency (T400 > 78% and b* < 2.2). These outstanding properties were attributed to the incorporation of fluorinated substituents as well as the rigid but contorted N2BC segments. For certain dianhydrides, the CANAL-F/CF3-derived CPIs exhibited the best optical properties due to their highest fluorine contents, while the CANAL-2F-derived CPIs exhibited the best thermal and mechanical properties, despite the lowest optical transmittance as a result of their most pronounced inter- and intramolecular interactions.

10 citations


Journal ArticleDOI
TL;DR: In this article , the authors performed identical ring-opening metathesis polymerization (ROMP) reactions on three different macromonomers (MM) in six solvents commonly used in ROMP with varying levels of purity.
Abstract: Ring-opening metathesis polymerization (ROMP) utilizing Grubbs’ third-generation catalyst ((H 2 IMes)(Cl) 2 (pyr) 2 RuCHPh) shows characteristics of living polymerizations, including molecular weights increasing with monomer conversion and the ability to make (multi)block copolymers. However, irreversible termination reactions still occur due to catalyst decomposition, leading to terminated chains, especially in the context of sterically demanding monomers such as macromonomers (MM). In this work, we performed identical ROMP reactions on three different MMs in six solvents commonly used in ROMP with varying levels of purity. The solvents included ethyl acetate (EtOAc), dichloromethane (CH 2 Cl 2 ), chloroform (CHCl 3 ), toluene , tetrahydrofuran (THF), and N,N- dimethylformamide (DMF). All polymerizations were conducted under air targeting a bottlebrush polymer backbone degree of polymerization ( N bb ) of 100. All three MMs included a norbornene on the α chain end and had molecular weights ( M n ) of ~4 kg/mol. They included one polystyrene MM with a bromine on the ω chain end and two poly( n -butyl acrylate) MMs with either a bromine or a trithiocarbonate group on the ω chain end. Solvent choice, and in some cases level of purity, led to significant differences in the propagation rate in these ROMP grafting-through reactions. Of the solvents tested , propagation rates in EtOAc and CH 2 Cl 2 were approximately 4-fold and 2-fold faster, respectively, than CHCl 3 , toluene, and THF for all MMs. Propagation was much slower in DMF for the polystyrene MM than all the other solvents, and on par with the slower solvents for the two poly( n -butyl acrylate) MMs tested. The purity of the solvent in some cases had a profound effect on the propagation rate: In the case of EtOAc, purification led to a 2-fold decrease in propagation rate; in contrast, purification of THF was required to observe full decomposition, the main polymer termination route in ROMP, we uncovered dramatic solvent effects, where the catalyst decomposed over ten times faster in THF and DMF than in toluene. Finally, studies targeting N bb = 500 or 1000 revealed that toluene, EtOAc, and CH 2 Cl 2 demonstrated the highest degree of “livingness” in ROMP . These results will enable the synthesis of complex polymer architectures using ROMP with a high degree of living character.

10 citations



Journal ArticleDOI
Ernest Opoku1
TL;DR: In this article , a systematic study on (3 + 2) cycloaddition reaction (32CA) of norbornene imide A with three-atom components (TACs), nitrile oxides and nitrones is presented.

8 citations


Journal ArticleDOI
15 Jan 2022-Fuel
TL;DR: In this article, a high-energy-density liquid fuel via catalytic dimerization of norbornene by the acidic zeolites was synthesized, and the mechanism and kinetics of isomerization-dimerization two-step process were demonstrated.

8 citations


Journal ArticleDOI
TL;DR: This methodology features the use of the low-cost industrial raw material CH2IF as the fluoromethyl source, an excellent functional group tolerance, and a broad ipso termination scope and can be expanded to the late-stage modification of biorelevant molecules.

8 citations


Journal ArticleDOI
TL;DR: In this paper , a series of novel HDPE/COC multiblock copolymers have been effectively obtained via chain shuttling copolymerization of ethylene and NBE.

8 citations


Journal ArticleDOI
TL;DR: In this article , a palladium/norbornene cooperative catalysis was used to construct polysubstituted indoles from oxime esters and aryl iodides.

7 citations


Journal ArticleDOI
TL;DR: A pathway featuring a norbornene synthase SdnG for the biosynthesis of sordaricin-the terpene precursor of antifungal natural product sordarin was reported in this paper .
Abstract: Abstract Pericyclases, enzymes that catalyze pericyclic reactions, form an expanding family of enzymes that have biocatalytic utility. Despite the increasing number of pericyclases discovered, the Diels-Alder cyclization between a cyclopentadiene and an olefinic dienophile to form norbornene, which is among the best-studied cycloadditions in synthetic chemistry, has surprisingly no enzymatic counterpart to date. Here we report the discovery of a pathway featuring a norbornene synthase SdnG for the biosynthesis of sordaricin-the terpene precursor of antifungal natural product sordarin. Full reconstitution of sordaricin biosynthesis reveals a concise oxidative strategy used by Nature to transform an entirely hydrocarbon precursor into the highly functionalized substrate of SdnG for intramolecular Diels-Alder cycloaddition. SdnG generates the norbornene core of sordaricin and accelerates this reaction to suppress host-mediated redox modifications of the activated dienophile. Findings from this work expand the scopes of pericyclase-catalyzed reactions and P450-mediated terpene maturation.

6 citations


Journal ArticleDOI
TL;DR: In this article , polysiloxane-functionalized polyolefin elastomer (Silo-70) was synthesized by anionic ring-opening polymerization of hexamethylcyclotrisiloxane (D3) and further used in terpolymerization with ethylene and cyclodiolefin (ethylidene norbornene or dicyclopentadiene).

6 citations


Journal ArticleDOI
TL;DR: A series of phosphinobenzenamine-based nickel complexes bearing substituted phenylphosphine ligands were synthesized and characterized in this article , and the nickel catalysts were able to conduct copolymerization of norbornene and methyl acrylate (MA) with high activity (3.76 × 105 g mol−1 h−1) to give high-molecular-weight functionalized cyclic olefin copolymers (COC) with reasonable MA incorporation (2.39−6.47 mol %).
Abstract: A series of phosphinobenzenamine-based nickel complexes bearing substituted phenylphosphine ligands were synthesized and characterized. These nickel complexes combined with methylaluminoxane (MAO) exhibited very high activity (∼106 g mol–1 h–1) and good thermal stability for norbornene polymerization. The nickel catalysts were able to conduct copolymerization of norbornene and methyl acrylate (MA) with high activity (3.76 × 105 g mol–1 h–1) to give high-molecular-weight functionalized cyclic olefin copolymer (COC) with reasonable MA incorporation (2.39–6.47 mol %). Moreover, the nickel catalysts also promote the copolymerization of ethylene and MA with moderate activity (∼104 g mol–1 h–1) to produce semicrystalline high-molecular-weight polar functionalized polyethylene (PE). The MA incorporation in the copolymer was controlled in a wide range (up to 15.5 mol %). These complexes without any sterically bulky substituent on the ligand are distinctive examples of earth-abundant nickel complexes toward the direct copolymerization of ethylene or norbornene with the challenging vinyl polar monomer MA.

Journal ArticleDOI
TL;DR: In this paper , a fluorescent poly(norbornene)-based copolymer (P1) containing rhodamine B in the spirocyclic ring form and 1,8-naphthalimide fluorophores has been designed and synthesized for sensing and detection of ATP.

Journal ArticleDOI
TL;DR: In this paper , the transformation of linear polyethylene-polyhedral oligomeric silsesquioxane (PE-POSS) copolymers into PE vitrimers through silyl ether metathesis was reported.

Journal ArticleDOI
TL;DR: In this article , the authors describe a general method for constructing highly efficient molecular brush-based catalytic nanoreactors utilizing postpolymerization modification (PPM) for aqueous catalysis.
Abstract: Polymer-based catalytic nanoreactors, with the characteristics of easy preparation, good dispersion, and facile modulation of molecular structures, have been widely applied for various organic transformations. Usually, polymeric nanoreactors are fabricated via the self-assembly of amphiphilic copolymers in water, while the disassembly and instability of the relevant nanoreactors often compromise their potential applicability. Molecular brushes (MBs), as a kind of polymer with high-density grafted side chains on the linear polymer main chain, can be rapidly self-assembled into highly ordered nanostructures even at low concentrations. This study reports the fabrication of catalytic nanoreactors from molecular brushes of poly[norbornene–poly(bromoethyl methacrylate-co-methyl methacrylate)]-co-poly[norbornene polyethylene glycol monomethyl ether] (P[NB-(BEMA-co-MMA)]-co-P[NB-PEG]). The amphiphilic molecular brush was synthesized by combining reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening metathesis polymerization (ROMP) techniques. Homogeneous catalysts, such as triethylenediamine and 4-(dimethylamino)pyridine analogues, were introduced by nucleophilic substitution with alkyl bromide on the side chain of molecular brushes. Furthermore, micellar catalytic nanoreactors were fabricated via self-assembly in deionized water. The resulted nanoreactors display high catalytic activities toward the Knoevenagel condensation reaction and acylation reaction of alcohol in water, respectively. This contribution describes a general method for constructing highly efficient molecular brush-based catalytic nanoreactors utilizing postpolymerization modification (PPM) for aqueous catalysis.

Journal ArticleDOI
TL;DR: In this paper , a series of norbornene-containing imidazolium-based mono-and di-cationic ILs (NBM-mIm and NBM-DILs) with different connectivity and spacer lengths were synthesized and characterized spectroscopically.
Abstract: Poly(norbornene)s and poly(ionic liquid)s are two different classes of attractive materials, which are known for their structural tunability and thermal stabilities, and have been extensively studied as gas separation membranes. The incorporation of ionic liquids (ILs) into the poly(norbornene) through post-polymerization has resulted in unique materials with synergistic properties. However, direct polymerization of norbornene-containing IL monomers as gas separation membranes are limited. To this end, a series of norbornene-containing imidazolium-based mono- and di-cationic ILs (NBM-mIm and NBM-DILs) with different connectivity and spacer lengths were synthesized and characterized spectroscopically. Subsequently, the poly(NBM-mIm) with bistriflimide [Tf2N−] and poly([NBM-DILs][Tf2N]2) comprising homo-, random-, and block- (co)polymers were synthesized via ring-opening metathesis polymerization using the air-stable Grubbs second-generation catalyst. Block copolymers (BCPs), specifically, [NBM-mIM][Tf2N] and [NBM-ImCnmIm] [Tf2N]2 (n = 4 and 6) were synthesized at two different compositions, which generated high molecular weight polymers with decent solubility relative to homo- and random (co)polymers of [NBM-DILs] [Tf2N]2. The prepared BCPs were efficiently analyzed by a host of analytical tools, including 1H-NMR, GPC, and WAXD. The successfully BCPs were cast into thin membranes ranging from 47 to 125 μm and their gas (CO2, N2, CH4, and H2) permeations were measured at 20 °C using a time-lag apparatus. These membranes displayed modest CO2 permeability in a non-linear fashion with respect to composition and a reverse trend in CO2/N2 permselectivity was observed, as a usual trade-off behavior between permeability and permselectivity.

Journal ArticleDOI
TL;DR: In this article , a frontal ring-opening metathesis polymerization (ROMP) was applied to polydicyclopentadiene (PDCPD)/hydroxylated barium titanate (BTOH) composites.

Journal ArticleDOI
01 Mar 2022-Polymer
TL;DR: In this article , the authors used Raman spectroscopy to monitor ring opening metathesis polymerization (ROMP) of cyclic olefins and their functional derivatives using Grubbs catalysts.

Journal ArticleDOI
31 May 2022
TL;DR: A new catalytic system based on palladium/norbornene and an S,O‐ligand for the meta‐C−H arylation of aryl ethers that significantly outperforms previously reported systems and demonstrates the unique ability to employ alkoxyarene substrates bearing electron donating and withdrawing substituents.
Abstract: Abstract Reversing the conventional site‐selectivity of C−H activation processes provides new retrosynthetic disconnections to otherwise unreactive bonds. Here, we report a new catalytic system based on palladium/norbornene and an S,O‐ligand for the meta‐C−H arylation of aryl ethers that significantly outperforms previously reported systems. We demonstrate the unique ability of this system to employ alkoxyarene substrates bearing electron donating and withdrawing substituents. Additionally, ortho‐substituted aryl ethers are well tolerated, overcoming the “ortho constraint”, which is the necessity to have a meta‐substituent on the alkoxyarene to achieve high reaction efficiency, by enlisting novel norbornene mediators. Remarkably, for the first time the monoarylation of alkoxyarenes is achieved efficiently enabling the subsequent introduction of a second, different aryl coupling partner to rapidly furnish unsymmetrical terphenyls. Further insight into the reaction mechanism was achieved by isolation and characterization of some Pd‐complexes—before and after meta C−H activation—prior to evaluation of their respective catalytic activities.

Journal ArticleDOI
TL;DR: In this article , a fluorescence lifetime imaging microscopy (FLIM) method was developed that overcomes the limitations of traditional molecular weight characterization techniques, which has limited ability to determine the molecular weight of polymers in real time without sample removal from the reaction mixture, with spatial resolution, and of insoluble polymers.
Abstract: Control of polymer molecular weight is critical for tailoring structure-function properties; however, traditional molecular weight characterization techniques have limited ability to determine the molecular weight of polymers in real time without sample removal from the reaction mixture, with spatial resolution, and of insoluble polymers. In this work, a fluorescence lifetime imaging microscopy (FLIM) method was developed that overcomes these limitations. The method is demonstrated with polynorbornene and polydicyclopentadiene, polymers derived from ruthenium-catalyzed ring-opening metathesis polymerization (ROMP). The polymer Mw, ranging from 35 to 570 kg/mol as determined by gel-permeation chromatography, was quantitatively correlated with the fluorescence lifetime. The revealed correlation then enabled time-resolved measurement of Mw during an ongoing ROMP reaction, requiring only 1 s per measurement (of a 45 μm × 45 μm polymer sample area), and provided spatial resolution, resulting in simultaneous characterization of polymer morphology. To provide the fluorescence signal, the initial reaction solutions contained a very low doping of a reactive norbornene monomer labeled with fluorescent boron dipyrromethene (BODIPY), such that 1 in every 107 monomers contained a fluorophore. The resulting FLIM visualization method enables the rapid determination of the molecular weights of growing polymers without removal from the reaction mixture and regardless of polymer solubility.

Journal ArticleDOI
TL;DR: A ring-opening metathesis polymerization (ROMP) copolymer P1 was designed and synthesized in this article , which can self-assemble nano aggregation in aqueous solution.

Journal ArticleDOI
TL;DR: In this paper , two complexes of oxovanadium and dioxovanadium with dipicolinate, 2-phenylyridine, and 4,4'-dimethoxy-2,2'-bipyridyl as precatalysts for 2-propen-1-ol and norborene oligomerizations are prepared.
Abstract: Polyolefins are used in everyday life, including in the production of many types of plastic. In addition, polyolefins account for over 50% of the polymers produced in the world. After conducting the oligomerization reactions of 2-propen-1-ol, 2-chloro-2-propen-1-ol, and norborene, polyolefins are obtained. In this report, two complexes of oxovanadium(IV) and dioxovanadium(V) with dipicolinate, 2-phenylyridine, and 4,4'-dimethoxy-2,2'-bipyridyl as precatalysts for 2-propen-1-ol, 2-chloro-2-propen-1-ol, and norborene oligomerizations are prepared. We present for the first time the new dipicolinate complex compound of oxovanadium(IV) with 4,4'-dimetoxy-2,2'-bipyridyl. Both complexes were tested for catalytic activity in the oligomerization reactions of 2-propen-1-ol, 2-chloro-2-propen-1-ol, and norbornene. Both synthesized complexes showed high catalytic activity in these oligomerization reactions, except for the oligomerization of norbornene.

Journal ArticleDOI
22 Jan 2022-Polymers
TL;DR: In this article , a post-modification of polynorbornene was carried out by inserting ethylene-vinyl acetate−vinyl alcohol blocks into its backbone via the cross-metathesis of poly(5-acetoxy-1-octenylene) and subsequent deacetylation and hydrogenation of the obtained multiblock copolymers.
Abstract: Commercial metathesis polynorbornene is used for the fabrication of high-damping coatings and bulk materials that dissipate vibration and impact energies. Functionalization of this non-polar polymer can improve its adhesive, gas barrier, and other properties, thereby potentially expanding its application area. With this aim, the post-modification of polynorbornene was carried out by inserting ethylene–vinyl acetate–vinyl alcohol blocks into its backbone via the cross-metathesis of polynorbornene with poly(5-acetoxy-1-octenylene) and subsequent deacetylation and hydrogenation of the obtained multiblock copolymers. For the first time, epoxy groups were introduced into the main chains of these copolymers, followed by the oxirane ring opening reaction. The influence of post-modification on the thermal, gas separation, and mechanical properties of the new copolymers was studied. It was shown that the gas permeability of the copolymer significantly depends on its composition, as well as on the amounts of hydroxyl and epoxy groups. The developed methods efficiently improve the barrier properties, reducing the oxygen permeability by 15–33 times in comparison with polynorbornene. The obtained results are promising for various applications and can be extended to a broader family of polydienes and other polymers containing backbone double bonds.

Journal ArticleDOI
TL;DR: Both axially and planar chiral ferrocene molecules with polychiral structures were synthesized via palladium/chiral norbornene cooperative catalysis and axial-to-planar diastereoinduction.


Journal ArticleDOI
TL;DR: In this paper , binuclear and mononuclear nickel α-diimine catalysts, as well as modified methylaluminoxane (MMAO) as a cocatalyst, are selected and utilized for 5-ethylidene-2-norbornene (ENB) homopolymerization.
Abstract: The present investigation is undertaken to provide a deeper understanding of the 5-ethylidene-2-norbornene (ENB) homopolymerization. To this end, binuclear and mononuclear nickel α-diimine catalysts, as well as modified methylaluminoxane (MMAO) as a cocatalyst, are selected and utilized. Al/Ni ratio of 1000 coupled with a temperature 25 °C and a polymerization time 12 h are chosen as the optimal statistics. It is shown that the highest obtained activity for binuclear and mononuclear catalysts are 511 and 478 kg polymer/mol, respectively. Thereafter, the characterization of the obtained poly 5-ethylidene-2-norbornene (PENB) is performed by fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Concerning the glass transition of cyclic polyolefin, DSC analysis reveals that catalyst structure is a determining factor (Tg binuclear: 176 °C and Tg mononuclear: 140 °C). As validated by dynamic mechanical thermal analysis (DMTA), it is realized that the alteration in the catalyst structure exerts a far-reaching influence on the polymer architecture. Surprisingly unexpectedly, excluding addition polymerization, an in-depth examination of polymer structure uncovers the potentially tenable participation of both cationic and ring-opening polymerization, albeit, with a diversified degree of contribution. Lastly, PENB is functionalized with three functional groups, and then the successful grafting of polar functional groups into modified cyclic polyolefin backbone is confirmed by NMR and FTIR spectroscopy.

Journal ArticleDOI
TL;DR: In this article , a microreactor-based enzymatic ring-opening polymerization (ROP) and metal-catalytic ringopening metathesis polymerization(ROMP) cascade reaction platform was developed for graft through synthesis of bottlebrush polymers.

Journal ArticleDOI
TL;DR: The modularity of thiol-norbornene photopolymerization is exploited to create a biomimetic hydrogel platform for 3D culture and differentiation of hiPSCs, enabling the understanding of each bioactive component on supporting hiPSC growth and ectodermal, mesodermal and endodermal fate commitment under identical soluble differentiation cues.

Journal ArticleDOI
01 Feb 2022-Polymer
TL;DR: In this article , an alternative single-step approach to fabricate NorHA is reported, which can be extended to other natural or synthesized biopolymers to prepare cytocompatible photo-crosslinked hydrogels.

Journal ArticleDOI
TL;DR: In this article , the authors report synthesis of two trithiocarbonate RAFT agents bearing either oxanorbornyl or norbornenyl moieties for use in a variety of different applications.

Journal ArticleDOI
TL;DR: In this paper , a polynorbornene skeleton was found that contains bicyclic norbornane units and cyclohexenyl methyl linkages, and was synthesized using a nickel catalyst in the presence of a controlled amount of ligands with low or moderate coordination ability.
Abstract: A new polynorbornene skeleton has been found that contains bicyclic norbornane units and cyclohexenyl methyl linkages. The polymers have been synthesized using a nickel catalyst in the presence of a controlled amount of ligands with low or moderate coordination ability. The backbone structure is the result of a vinylic addition polymerization, via sequential insertions of norbornene into a Ni–C bond (bicyclic units) combined with an unusual ring opening of the norbornene structure by a β-C elimination (cyclohexenyl methyl units) to give a new Ni–C(alkyl) bond that continues the polymerization. The ring opening events are favored when the rate of propagation of the vinylic addition polymerization decreases, and this can be modulated by making the coordination of norbornene to the metal center less favorable using additional ligands.