Showing papers on "Ring-opening metathesis polymerisation published in 2018"
TL;DR: A general strategy for the synthesis of block copolymers in aqueous milieu using a commercially available ROMP catalyst and a macroinitiator approach is reported, which allows for excellent control in the preparation of blockCopolymer in water.
Abstract: Water-soluble and amphiphilic polymers are of great interest to industry and academia, as they can be used in applications such as biomaterials and drug delivery. Whilst ring-opening metathesis polymerization (ROMP) is a fast and functional group tolerant methodology for the synthesis of a wide range of polymers, its full potential for the synthesis of water-soluble polymers has yet to be realized. To address this, we report a general strategy for the synthesis of block copolymers in aqueous milieu using a commercially available ROMP catalyst and a macroinitiator approach. This allows for excellent control in the preparation of block copolymers in water. If the second monomer is chosen such that it forms a water-insoluble polymer, polymerization-induced self-assembly (PISA) occurs and a variety of self-assembled nano-object morphologies can be accessed.
71 citations
TL;DR: In this article, a ring-opening metathesis polymerization (ROMP) of norbornene was used to construct blue thermally activated delayed fluorescence (TADF) polymers.
Abstract: The exploitation of blue polymer emitters is of great importance for the application of solution-processed organic light-emitting diodes (OLEDs) in full color display. The highly efficient blue thermally activated delayed fluorescence (TADF) polymers are rarely reported up to now. Herein, we report an efficient approach to construct blue TADF polymers by ring-opening metathesis polymerization (ROMP) of norbornene. By side-chain engineering strategy, the polymers are endowed with distinct TADF features. By use of these blue polymeric emitters, the nondoped OLEDs achieved a maximum external quantum efficiency of 7.3% with the Commission Internationale de L’Eclairage (CIE) coordinates of (0.20, 0.29), which represents the state-of-the-art device performance for the TADF-based blue polymer light-emitting diodes (PLEDs).
65 citations
TL;DR: Aqueous-phase ring-opening metathesis polymerization-induced self-assembly (ROMPISA) was used in this paper for forming micellar polymer nanoparticles at room temperature and high solids concentration.
Abstract: We report aqueous-phase Ring-Opening Metathesis Polymerization-Induced Self-Assembly (ROMPISA) for forming well-defined micellar polymer nanoparticles at room temperature and high solids concentration (20 w/w%). This is achieved with a new polymerization initiator, in the form of a water-soluble cationic Hoveyda-Grubbs second generation catalyst. This reaction was used in water to produce diblock copolymers from norbornenyl monomers, which then self-assemble into myriad nanostructure morphologies for which a phase diagram was constructed. Additionally, the living nature of the polymerization initiated by the aqueous initiator was confirmed, as shown by kinetic evaluation under mild conditions in water.
57 citations
TL;DR: In this article, a facile and efficient synthetic grafting-through strategy for preparing well-defined bottlebrush block copolymers (BBCPs) was developed through a combination of living anionic polymerization and ring-opening metathesis polymerization (ROMP).
Abstract: A facile and efficient synthetic grafting-through strategy for preparing well-defined bottlebrush block copolymers (BBCPs) was developed through a combination of living anionic polymerization (LAP) and ring-opening metathesis polymerization (ROMP). ω-End-norbornyl polystyrene (NPSt) and poly(4-tert-butoxystyrene) (NPtBOS) were synthesized by LAP using terminator of chlorine moiety containing silane-protecting amine and coupled with a subsequent amidation using norbornyl activated ester. Bottlebrush homopolymers of NPSt were obtained by ROMP with ultrahigh molecular weights (MWs, Mw = 2928 kDa) and narrow molecular weight distributions (MWDs, Đ = 1.07) at high degree of polymerizations (DPw = 1084). Well-defined BBCPs with ultrahigh MWs (Mw ∼ 3055 kDa) and narrow MWDs (Đ ∼ 1.13) were synthesized through sequential ROMP of NPSt with NPtBOS. The effect of ultrahigh MWs was investigated by self-assembly of the BBCPs in which the phase-separated BBCPs presented periodic lamellar structures and exhibited struct...
47 citations
TL;DR: In this article, a reversible ring-opening metathesis polymerization of cyclopentene derivatives in the bulk state was reported, which was characterized by differential scanning calorimetry and rheological tests.
Abstract: Reversible transformations in bulk polymers offer numerous possibilities for materials remodeling and reprocessing. While reversible systems based on dynamic covalent chemistry such as the Diels–Alder reaction and transesterification have been intensively studied to enable local bond dissociation and formation, reports regarding the reversion from bulk network polymers to monomers are rare. Herein, we report a reversibly polymerizable system based on ring-opening metathesis polymerization of cyclopentene derivatives in the bulk state. The network polymer is thermodynamically stable and mechanically robust at room temperature and readily depolymerizes at elevated temperatures to yield liquid monomers that are repolymerized to cross-linked polymers by simply cooling to room temperature. This reversible process was characterized by differential scanning calorimetry and rheological tests.
46 citations
TL;DR: A review of light-activated olefin metathesis reactions from the development of novel complexes that can be initiated photochemically to recently reported applications of photo-induced olefins, as well as the bright newly emerging field of photoredox-mediated metal-free ROMP can be found in this paper.
Abstract: Olefin metathesis is one of the most important methods to form carbon–carbon double bonds and has found many applications in industry and academia. The ability to initiate the reaction using external stimulus such as light, with high spatial and temporal resolution is highly advantageous and provides creative novel opportunities in organic syntheses and material sciences. This review article covers recent advances in light-activated olefin metathesis reactions from the development of novel complexes that can be initiated photochemically to recently reported applications of photoinduced olefin metathesis, as well as the bright newly emerging field of photoredox-mediated metal-free ROMP. 1 Introduction 2 Light-Activated Olefin Metathesis Complexes 2.1 Sulfur-Chelated Hoveyda–Grubbs-Type Complexes 2.2 Nitrogen-Chelated Hoveyda–Grubbs-Type Complexes 2.3 Catalyst Activation with Photoacid Generators 2.4 Phototuning of Active Complexes 2.5 Photoactivation of Non-Grubbs-Type Olefin Metathesis Complexes 3 Photoredox-Mediated Metal-Free ROMP 4 Applications of Photoinduced Olefin Metathesis 4.1 Chromatic Orthogonal Olefin Metathesis 4.2 UV-Filter-Assisted Olefin Metathesis 4.3 Photolithographic Olefin Metathesis Polymerization 5 Conclusions
39 citations
TL;DR: A series of vanadium(V)-alkylidene complexes containing pentachlorophenoxy ligand of type, V(CHSiMe3)(N-2,6-R2C6H3)(OC6Cl5)(PMe3)2 [R = H, Cl, F, CH3], have been prepared by X-ray crystallographic analysis.
32 citations
TL;DR: Polypentenamer macroinitiators are synthesized through variable temperature ring opening metathesis polymerization of 3-cyclopentenyl α-bromoisobyrate, which has sufficient ring strain (ΔHp = −22.6 kJ mol−1) to produce targeted molar mass ( 1000 kg mol-1) and Đ = 1.33 as mentioned in this paper.
Abstract: Polypentenamer macroinitiators are synthesized through variable temperature ring opening metathesis polymerization of 3-cyclopentenyl α-bromoisobutyrate, which has sufficient ring strain (ΔHp = −22.6 kJ mol–1) to produce targeted molar mass ( 1000 kg mol–1) and Đ = 1.33. This system exhibits high synthetic versatility and control with a unique flexible backbone to expand the suite of densely grafted polymers.
28 citations
TL;DR: In this paper, the authors demonstrate that one-dimensional linear polymers with flexible backbones prepared through ring opening metathesis polymerization can be highly porous, allowing facile access to diversified porous organic polymers having tunable mechanical/chemical properties bearing different functionalities.
Abstract: Highly porous and solution processable organic polymers that can be structurally tailored for various applications are in great demand Previously reported strategies to prepare porous polymers usually rely on a high level of cross-linking or structurally rigid polymer backbones We now demonstrate that one-dimensional linear polymers with flexible backbones prepared through ring opening metathesis polymerization can be highly porous This new strategy allows facile access to diversified porous organic polymers having tunable mechanical/chemical properties bearing different functionalities
26 citations
TL;DR: In this paper, the preparation of cyclic ferrocenyl olefins with various substituents and different ring sizes by ring-closing metathesis (RCM) was reported.
Abstract: We report the preparation of cyclic ferrocenyl olefins with various substituents and different ring sizes by ring-closing metathesis (RCM). These ferrocene-containing monomers were subject to ring-opening metathesis polymerization (ROMP), leading to main-chain ferrocene-containing homopolymers, random copolymers, and block copolymers. Depending on the substituents, ferrocenyl homopolymers are semicrystalline or amorphous with good solubility. A semicrystalline polymer was used in the crystallization-driven self-assembly (CDSA) of block copolymers to generate platelet nanostructures.
24 citations
TL;DR: The unique all-carbon backbone formed in the AROMP of bicyclo[4.2.0]oct-1(8)-ene-8-carboxamides and cyclohexene provides a platform for the nontemplated preparation of materials with specific sequences of side chains.
Abstract: We report the formation of oligomers with side-chain sequence control using ruthenium-catalyzed alternating ring-opening metathesis polymerization (AROMP). These oligomers are prepared through sequential, stoichiometric addition of bicyclo[4.2.0]oct-1(8)-ene-8-carboxamide (monomer A) at 85 °C and cyclohexene (monomer B) at 45 °C to generate sequences up to 24 monomeric units composed of (A-alt-B)n and (A′-alt-B)n microblocks, where n ranges from 1 to 6. Herein, monomer A has an alkyl side chain, and monomer A′ has a glycine methyl ester side chain. Increasing microblock size from one to six results in an increasing water contact angle on spin-coated thin films, despite the constant ratio of hydrophilic and hydrophobic moieties. However, a disproportionately high contact angle was observed when n equals 2. Thus, the unique all-carbon backbone formed in the AROMP of bicyclo[4.2.0]oct-1(8)-ene-8-carboxamides and cyclohexene provides a platform for the nontemplated preparation of materials with specific seque...
TL;DR: In this paper, the molecular characteristics of the macromolecular brushes were determined by 1H NMR spectroscopy and size exclusion chromatography equipped with various detectors, and significant differences were found between the brush copolymers at the crystalline lamellar and spherulitic superstructure levels.
Abstract: Statistical and block copolymerization of poly(l-lactide) (PLLA) and poly(e-caprolactone) (PCL) macromonomers having an end norbornenyl group was performed via ring-opening metathesis polymerization (ROMP) to produce the corresponding statistical and block brush copolymers consisting of PLLA and PCL side chains on a polynorbornene (PNBE) backbone. The molecular characteristics of the macromolecular brushes were determined by 1H NMR spectroscopy and size exclusion chromatography equipped with various detectors. These complex topologies allow addressing important questions on the physics of semicrystalline polymers. These include the role of (i) a doubly grafted PCL or PLLA chain on a NBE moiety (in the macromonomers) and the role of (ii) brush architecture on the crystallization behavior and dynamics of block and statistical copolymers. Significant differences were found between the macromonomers and the corresponding brush copolymers at the crystalline lamellar and spherulitic superstructure levels. In th...
TL;DR: To the best of the knowledge, this is the first example of a photogenerated NHC, exploitation in photoROMP has resulted in a simplified process compared to current photocatalysts, because only stable commercial or easily synthesized reagents are required.
Abstract: 1,3-Bis(mesityl)imidazolium tetraphenylborate (IMesH+ BPh4- ) can be synthesized in one step by anion metathesis between the corresponding imidazolium chloride and sodium tetraphenylborate. In the presence of 2-isopropylthioxanthone (sensitizer), an IMes N-heterocyclic carbene (NHC) ligand can be photogenerated under irradiation at 365 nm through coupled electron/proton transfer reactions. By combining this tandem NHC photogenerator system with metathesis inactive [RuCl2 (p-cymene)]2 precatalyst, the highly active RuCl2 (p-cymene)(IMes) complex can be formed in situ, enabling a complete ring-opening metathesis polymerization (ROMP) of norbornene in the matter of minutes at room temperature. To the best of our knowledge, this is the first example of a photogenerated NHC. Its exploitation in photoROMP has resulted in a simplified process compared to current photocatalysts, because only stable commercial or easily synthesized reagents are required.
TL;DR: In this paper, Fucoidan-mimetic glycopolymers were successfully fabricated through microwave-assisted ring-opening metathesis polymerization (ROMP) in an emulsion system.
Abstract: The approach developed here offers distinct and well-defined glycopolymers for deciphering the biological roles of natural bioactive polysaccharides. Fucose monomers were chemically synthesized and decorated with specific sulfation patterns including unsulfate, monosulfate, disulfate, and trisulfate groups. The six fucoidan-mimetic glycopolymers (18–23) were successfully fabricated through microwave-assisted ring-opening metathesis polymerization (ROMP) in an emulsion system. The molecular weight (Mw), polydispersity index (PDI), and multiple functional groups were fully characterized by SEC-MALLS-RI and NMR spectroscopy. Three glycopolymers (19, 21, 23) associated with 2-O-sulfation exhibited better inhibitory effects on the H1N1 virus, while glycopolymers (19, 20) with monosulfate groups were more effective against the H3N2 virus. These findings would promote the development of novel anti-influenza A virus (IAV) drugs based on natural fucoidans.
TL;DR: A Grubbs-Hoveyda type catalyst with a N-pentiptycenyl, N-cyclohexyl-NHC ligand provides poly(nbe-alt-coe) with an excellent degree of alternation while lacking significant activity in the homopolymerization of cyclooctene.
TL;DR: The synthesis and characterization of synthetic polymer aerogels based on dendritic-type urethane-norbornene monomers found that it is not the aliphatic or aromatic core that determines phase separation, but rather the solubility of the polymeric backbone (polynorbornenes) that is in both cases the same.
Abstract: We report the synthesis and characterization of synthetic polymer aerogels based on dendritic-type urethane-norbornene monomers. The core of those monomers is based either on an aromatic/rigid (TIPM/Desmodur RE), or an aliphatic/flexible (Desmodur N3300) triisocyanate. The terminal norbornene groups (three at the tip of each of the three branches) were polymerized via ROMP using the inexpensive 1st generation Grubbs catalyst. The polymerization/gelation conditions were optimized by varying the amount of the catalyst. The resulting wet-gels were dried either from pentane under ambient pressure at 50 °C, or from t-butanol via freeze-drying, or by using supercritical fluid (SCF) CO2. Monomers were characterized with high resolution mass spectrometry (HRMS), 1H- and solid-state 13C-NMR. Aerogels were characterized with ATR-FTIR and solid-state 13C-NMR. The porous network was probed with N2-sorption and SEM. The thermal stability of monomers and aerogels was studied with TGA, which also provides evidence for the number of norbornene groups that reacted via ROMP. At low densities ( 90%), mostly macroporous materials; aerogels based on the aliphatic/flexible core were fragile, whereas aerogels containing the aromatic/rigid core were plastic, and at even lower densities (0.03 g cm−3) foamy. At higher densities (0.2–0.7 g cm−3) all materials were stiff, strong, and hard. At low monomer concentrations all aerogels consisted of discrete primary particles that formed spherical secondary aggregates. At higher monomer concentrations the structure consisted of fused particles with the size of the previous secondary aggregates, due to the low solubility of the developing polymer, which phase-separated and formed a primary particle network. Same-size fused aggregates were observed for both aliphatic and aromatic triisocyanate-derived aerogels, leading to the conclusion that it is not the aliphatic or aromatic core that determines phase separation, but rather the solubility of the polymeric backbone (polynorbornene) that is in both cases the same. The material properties were compared to those of analogous aerogels bearing only one norbornene moiety at the tip of each branch deriving from the same cores.
TL;DR: In this paper, a series of allylic substituted cyclopentene monomers with increasing steric bulk are investigated by ring opening metathesis polymerization to understand the effects of these substituents on the microstructural outcomes of the resulting polypentenamers.
TL;DR: The ring-opening metathesis polymerization (ROMP) of (+)-Vince lactam is reported in this paper, where a small amount of trans double bonds (ca. 5%) formed.
Abstract: The ring-opening metathesis polymerization (ROMP) of (+)-Vince lactam [(S)-azabicyclo[2.2.1]hept-5-en-3-one] (1) and its N-benzyl, N-trimethylsilyl (TMS), and N-tert-butoxycarbonyl (Boc) derivatives (2a–c) is reported. Highly cis-syndiotactic (st) poly(Vince lactam) was readily accessible by using the cyclometalated ruthenium complex Ru[CH(2-OiPr-Ph)](Piv)(1-mesityl-3-C4H8-imidazol-2-ylidene) (Piv =2,2-dimethylpropanoate) (4); however, small amounts of trans double bonds (ca. 5%) formed. Highly cis-st (>98%) polymers were accessible by the action of the monoaryloxide pyrrolide (MAP) type complexes W(N-2,6-iPr2C6H3)(CHCMe2Ph)(Pyr)(HMTO) (Pyr = pyrrolide, HMTO = 2,6-(2,4,6-Me3C6H2)2C6H3O) (7) and W(O)(CHCMe2Ph)(PMe2Ph)(Me2Pyr)(TPPO) (TPPO = 2,3,5,6-tetraphenylphenolate) (8). Complementary, cis-isotactic (>98% cis-it) polymers were prepared by the action of Mo(N-2,6-Me2C6H3)(CHCMe2Ph)(OBiphen) (OBiphen = 3,3′-di-tert-butyl-5,5′,6,6′-tetramethyl-1,1′-biphenyl-2,2′-diolate) (5) and its tungsten analogue W(N-2,...
TL;DR: In this paper, a ring-opening metathesis polymerization (ROMP) was performed on three norbornene-substituted polyhedral oligomeric silsesquioxane (POSS) monomers with different spacers.
TL;DR: Highly active catalysts for the ring-opening metathesis polymerization (ROMP) of cyclic olefins (norbornene, cyclopentenes, cycloheptene) can be generated in situ by premixing V(CHSiMe3)(NC6F5)(O-2,6-iPr2C6H3)(PMe3)2 (1) with 1.0 equiv.
01 Mar 2018
TL;DR: In this paper, the authors demonstrate that one-dimensional linear polymers with flexible backbones prepared through ring opening metathesis polymerization can be highly porous, allowing facile access to diversified porous organic polymers having tunable mechanical/chemical properties bearing different functionalities.
Abstract: Highly porous and solution processable organic polymers that can be structurally tailored for various applications are in great demand. Previously reported strategies to prepare porous polymers usually rely on a high level of cross-linking or structurally rigid polymer backbones. We now demonstrate that one-dimensional linear polymers with flexible backbones prepared through ring opening metathesis polymerization can be highly porous. This new strategy allows facile access to diversified porous organic polymers having tunable mechanical/chemical properties bearing different functionalities.
TL;DR: A general method for the preparation of bicyclo[4.2.0]oct-(8)-ene-8-carboxy derivatives is described, where the central 8-cyano intermediate provides entry to five different functional group substituents on the alkene.
Abstract: Bicyclo[4.2.0]oct-1(8)-ene-8-carboxamides undergo alternating ring-opening metathesis polymerization (AROMP) with cyclohexene. Herein, a general method for the preparation of bicyclo[4.2.0]oct-(8)-ene-8-carboxy derivatives is described. The central 8-cyano intermediate provides entry to five different functional group substituents on the alkene. These monomers were tested as potential substrates for AROMP with cyclohexene. In addition to the carboxamide, the carboxynitrile and carboxaldehyde are also substrates for AROMP. In the case of the carboxaldehyde, the polymer is regioregular. However, the addition of carboxynitrile is stereoirregular and slow.
TL;DR: In this paper, a ring-opening metathesis polymerization (ROMP) approach was proposed for functionalized cyclooctenes (FCOEs) with adjacent heteroatoms.
Abstract: Functionalized cyclooctenes (FCOEs) are important monomers in ring-opening metathesis polymerization (ROMP). Herein, a new library of disubstituted FCOEs bearing adjacent heteroatoms were synthesized and applied in ROMP. To address the issues associated with the handling of the reactive thienyl chloride intermediate, a two-step continuous flow method has been developed to prepare 5-thio-6-chlorocyclooctene compounds from abundant cyclooctadiene starting materials. These newly synthesized FCOE monomers were subsequently polymerized through ROMP, giving rise to a range of functionalized polymers with high molecular weights. Furthermore, we demonstrated that the thermal properties of these polymers could be fine-tuned by changing the functional groups in the FCOE monomers. We expect that this functionalization-polymerization strategy will enable the preparation of a range of polymeric materials with complex structures.
TL;DR: The use of ring-opening metathesis polymerization (ROMP) to synthesize unsaturated protein-reactive PEG analogs, which were found to be nontoxic and readily conjugated to free amines on the protein hen egg-white lysozyme.
TL;DR: Ring-opening metathesis polymerization (ROMP) of 1,5-cyclooctadiene (COD) in miniemulsion was conducted utilizing a water-soluble TEGylated ruthenium alkylidene catalyst that was designed to underg...
Abstract: Ring-opening metathesis polymerization (ROMP) of 1,5-cyclooctadiene (COD) in miniemulsion was conducted utilizing a water-soluble TEGylated ruthenium alkylidene catalyst that was designed to underg...
TL;DR: In this article, a ring opening metathesis polymerization (ROMP) of exo-1,4,4a,9,9a,10-hexahydro-9,10(1′,2′)-benzeno-l,4-methanoanthracene (HBM) and dicyclopentadiene (DCPD) or norbornene (NBE) using WCl6/i-Bu3Al/ethanol/1-hexene catalyst system, followed by hydrogenation of double bonds.
Abstract: Cyclic olefin polymers (COPs) with high glass transition temperature, high transparency (higher than 80%) in the visible light range, excellent thermal stability and outstanding mechanical properties have been synthesized by effective ring opening metathesis polymerization (ROMP) of exo-1,4,4a,9,9a,10-hexahydro-9,10(1′,2′)-benzeno-l,4-methanoanthracene (HBM) and dicyclopentadiene (DCPD) or norbornene (NBE) using WCl6/i-Bu3Al/ethanol/1-hexene catalyst system, followed by hydrogenation of double bonds. 1-Hexene acted as a molecular weight controller in the polymerization reaction, tuning the number-average molecular weight (Mn) of P-HBM from 5.8 × 104 to 41.1 × 104. The monomer composition and thermal properties of the copolymers were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The saturated polymers exhibited high decomposition temperatures (Td) around 340 °C and glass transition temperatures (Tg) in the range from 117.5 °C to 219.7 °C. What is more, tensile tests indicated that the mechanical properties of the COPs could be effectively tuned in a wide range by introducing varying amount of small cyclic olefin such as DCPD or NBE.
TL;DR: A supramolecular complex gel with Zn2+, which is a metal with a lower binding affinity, demonstrated fast self-healing properties, without any additional external stimuli, and its mechanical properties were completely recovered.
Abstract: We induced a terpyridine moiety into a norbornene-based polymer to demonstrate its self-healing property, without an external stimulus, such as light, heat, or healing agent, using metal⁻ligand interactions. We synthesized terpyridine incorporated norbornene-based polymers using a ring-opening metathesis polymerization. The sol state of diluted polymer solutions was converted into supramolecular assembled gels, through the addition of transition metal ions (Ni2+, Co2+, Fe2+, and Zn2+). In particular, a supramolecular complex gel with Zn2+, which is a metal with a lower binding affinity, demonstrated fast self-healing properties, without any additional external stimuli, and its mechanical properties were completely recovered.
TL;DR: In this article, a ring-opening metathesis polymerization (ROMP) of 13C-labeled dialkoxy-substituted [2,2] paracyclophane-1,9-dienes (M) using the Grubbs second generation ruthenium carbene complex (G2) was performed.
Abstract: Selectively main chain 13C-labeled poly(p-phenylenevinylene)s (PPVs) were synthesized by ring-opening metathesis polymerization (ROMP) of 13C-labeled dialkoxy-substituted [2,2] paracyclophane-1,9-dienes (M) using the Grubbs second generation ruthenium carbene complex (G2). Analysis of the natural abundance and 13C-labeled PPVs by NMR spectroscopy showed no main chain structural defects for these polymers. Comparison of the in situ 1H and 13C NMR spectroscopy during the ROMP of labeled and unlabeled monomer enabled the active ruthenium carbene chain ends present during the initiation and propagation reaction to be definitively characterized. Using 13C NMR spectroscopy, the regiochemistry of the propagation of the asymmetric monomer M with G2 was found to be essentially regiorandom.