Tandem Ring-opening Metathesis Research Articles

Cross-Linked Polyolefins through Tandem ROMP/Hydrogenation.

Cross-linked polyolefins have important advantages over their thermoplastic analogues, particularly improved impact strength and abrasion resistance, as well as increased chemical and thermal stability; however, most strategies for their production involve postpolymerization cross-linking of polyolefin chains. Here, a tandem ring-opening metathesis polymerization (ROMP)/hydrogenation approach is presented. Cyclooctene (COE)-co-dicyclopentadiene (DCPD) networks are first synthesized using ROMP, after which the dispersed Ru metathesis catalyst is activated for hydrogenation through the addition of hydrogen gas. The reaction temperature for hydrogenation must be sufficiently high to allow mobility within the system, as dictated by thermal transitions (i.e., glass and melting transitions) of the polymeric matrix. COE-rich materials exhibit branched-polyethylene-like crystallinity (25% crystallinity) and melting points (Tm = 107 °C), as well as excellent ductility (>750% extension), while majority DCPD materials are glassy (Tg = 84 °C) and much stiffer (E = 710 MPa); all materials exhibit high tensile toughness. Importantly, hydrogenation of olefins in these cross-linked materials leads to notable improvements in oxidative stability, as saturated networks do not experience the same substantial degradation of mechanical performance as their unsaturated counterparts upon prolonged exposure to air.

MYC-Targeting Inhibitors Generated from a Stereodiversified Bicyclic Peptide Library.

Here, we present the second generation of our bicyclic peptide library (NTB), featuring a stereodiversified structure and a simplified construction strategy. We utilized a tandem ring-opening metathesis and ring-closing metathesis reaction (ROM-RCM) to cyclize the linear peptide library in a single step, representing the first reported instance of this reaction being applied to the preparation of macrocyclic peptides. Moreover, the resulting bicyclic peptide can be easily linearized for MS/MS sequencing with a one-step deallylation process. We employed this library to screen against the E363-R378 epitope of MYC and identified several MYC-targeting bicyclic peptides. Subsequent in vitro cell studies demonstrated that one candidate, NT-B2R, effectively suppressed MYC transcription activities and cell proliferation.

Polymeric α-diimine palladium catalysts for olefin (co)polymerization

In this contribution, a series of α-diimine palladium complexes with two vinyl units were designed and synthesized. Tandem ring opening metathesis polymerization/cross metathesis of cycloolefins in the presence of these complexes as chain-transfer agents resulted in a series of well-defined polymeric α-diimine Pd catalysts with improved catalytic performances. These polymeric Pd complexes can catalyze polymerization of ethylene and result in increased molecular weight of polyethylene products compared with their molecular analogues. In the polymerization of 1-hexene, the polymeric catalysts led to less isomerization, resulting in increased conversions of 1-hexene and higher molecular weights. Moreover, polymeric palladium catalysts show improved tolerance to polar comonomers, leading to higher activities as well as higher molecular weights in ethylene–methyl acrylate copolymerization. Most importantly, tuning of catalyst performance can be achieved by varying the structure or amount of cyclic monomer used in the preparation of these well-defined polymeric catalysts starting from the simple homogeneous platform.

The synthesis and properties research of functionalized polyolefins

This work demonstrated a tandem ROMP/hydrogenation approach for the preparation of functionalized polyolefins and their properties were investigated.

Block Copolymer Electrolytes with Excellent Properties in a Wide Temperature Range

A series of block copolymers (BCPs) with a polynorbornene backbone containing short poly(ethylene oxide) (PEO) side chains and rigid side chains were synthesized by tandem ring-opening metathesis p...

High-performance all-polymer dielectric and electrical energy storage materials containing conjugated segment and multi-fluorinated pendants

Highly polarizable block copolymer consisting of insulating polynorbornene and conductive polyacetylene segments with multi-fluorinated pendants was synthesized by tandem ring-opening metathesis polymerization and metathesis cyclopolymerization, which displayed relatively high dielectric constant of 8, very low dielectric loss of about 0.003, and enhanced energy density of 11.45 J cm−3 at the electric field strength of 450 MV m−1 accompanied with an excellent charge-discharge efficiency of 99%. The outstanding dielectric and energy storage capability were mainly attributed to high dipole moment of multi-fluorinated groups on polymer backbone and the interfacial polarization derived from the unique self-assembled nanostructure of block copolymers.

α,ω-Di(vinylene carbonate) telechelic polyolefins: Synthesis by metathesis reactions and studies as potential precursors toward hydroxy-oxazolidone-based polyolefin NIPUs

Current polyurethane (PU) industrial and academic research aims at developing non-isocyanate PUs, referred to as NIPUs. Within this context, we report herein the synthesis of original vinylene carbonate (VC) compounds, subsequently used as chain-transfer agents (CTAs) towards the preparation of α,ω-di(VC) telechelic (co)polyolefins from the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins. Thus, (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl acrylate (VC1), bis((5-methyl-2-oxo-1,3-dioxol-4-yl)methyl) fumarate (VC2), and bis((5-methyl-2-oxo-1,3-dioxol-4-yl)methyl) (E)-hex-3-enedioate (VC3) were synthesized from 4-(hydroxymethyl)-5-methyl-1,3-dioxol-2-one (DMDO-OH). Among these, only VC3 successfully and selectively afforded well-defined α,ω-di(vinylene carbonate) telechelic polyolefins, namely di(VC3)-PCOE and di(VC3)-P(NB-co-CDT), from the ROMP/CM of COE, and norbonene (NB)/trans,trans,cis-1,5,9-cyclododecatriene (CDT), respectively, using Grubbs’ 2nd-generation ruthenium catalyst (G2) under mild operating conditions (CH2Cl2, 40 °C, 3 h). Preliminary investigations on the reactivity of a model VC, namely 4,5-dimethyl-1,3-dioxol-2-one (DMDO), towards nucleophiles such as a primary or secondary amine, promisingly showed the formation of hydroxy-oxazolidone compounds 1 and 2, and oxo-urethane 3 species, respectively. Yet, the ultimate reaction of di(VC3)-PCOE with 2,2′-(ethylenedioxy)bis(ethylamine) (EDR-148) did not give the expected poly(di(hydroxy-oxazolidone)polyolefin) polyaddition type of NIPUs; competing amidation and/or dehydration or urea formation reactions evidenced by detailed NMR, FTIR and MS analyses, were proposed to account for this inefficiency.

α,ω-Epoxide, Oxetane, and Dithiocarbonate Telechelic Copolyolefins: Access by Ring-Opening Metathesis/Cross-Metathesis Polymerization (ROMP/CM) of Cycloolefins in the Presence of Functional Symmetric Chain-Transfer Agents.

Epoxide- and oxetane-α,ω-telechelic (co)polyolefins have been successfully synthesized by the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins using Grubbs’ second-generation catalyst (G2) in the presence of a bifunctional symmetric alkene epoxide- or oxetane-functionalized chain-transfer agent (CTA). From cyclooctene (COE), trans,trans,cis-1,5,9-cyclododecatriene (CDT), norbornene (NB), and methyl 5-norbornene-2-carboxylate (NBCOOMe), with bis(oxiran-2-ylmethyl) maleate (CTA 1), bis(oxetane-2-ylmethyl) maleate (CTA 2), or bis(oxetane-2-ylmethyl) (E)-hex-3-enedioate (CTA 3), well-defined α,ω-di(epoxide or oxetane) telechelic PCOEs, P(COE-co-NB or -NBCOOMe)s, and P(NB-co-CDT)s were isolated under mild operating conditions (40 or 60 °C, 24 h). The oxetane CTA 3 and the epoxide CTA 1 were revealed to be significantly more efficient in the CM step than CTA 2, which apparently inhibits the reaction. Quantitative dithiocarbonatation (CS2/LiBr, 40 °C, THF) of an α,ω-di(epoxide) telechelic P(NB-co-CDT) afforded a convenient approach to the analogous α,ω-bis(dithiocarbonate) telechelic P(NB-co-CDT). The nature of the end-capping function of the epoxide/oxetane/dithiocarbonate telechelic P(NB-co-CDT)s did not impact their thermal signature, as measured by DSC. These copolymers also displayed a low viscosity liquid-like behavior and a shear thinning rheological behavior.

Solid Polymer Electrolytes with Excellent High-Temperature Properties Based on Brush Block Copolymers Having Rigid Side Chains.

A series of brush block copolymers (BBCPs) with polynorbornene backbones containing poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS, which is a rigid chain) and poly(ethylene oxide) (PEO) side chains were synthesized by tandem ring-opening metathesis polymerizations. The weight fractions of PEO in BBCPs are similar, and the degrees of polymerization (DPs) of PEO side chains are the same while the DPs of PMPCS are different. The bulk self-assembling behaviors were studied by small-angle X-ray scattering (SAXS). The neat BBCPs cannot form ordered nanostructures. However, after the doping of lithium salt, the BBCPs self-assemble into lamellar (LAM) structures. When the DPs of the PEO and PMPCS side chains are similar, the LAM structure is more ordered, which is attributed to the more flat interface between PMPCS and PEO phases. The ionic conductivity (σ) values of the BBCP/lithium salt complex with the most ordered LAM structure at different temperatures were measured. The σ value increases with increasing temperature in the range of 40-200 °C, and the relationship between σ and T fits the Vogel-Tamman-Fulcher (VTF) equation. The σ value at 200 °C is 1.58 × 10-3 S/cm, which is one of the highest values for PEO-based polymer electrolytes. These materials with high σ values at high temperatures may be used in high-temperature lithium ion batteries.

Tandem Ring-Opening Metathesis - Vinyl Insertion Polymerization: Fundamentals and Application to Functional Polyolefins.

The accomplishments in the copolymerization of ethylene with cyclic olefins such as norborn-2-ene or cis-cyclooctene via tandem ring-opening metathesis polymerization (ROMP) - vinyl insertion polymerization (VIP) are outlined. This approach provides polyolefins with high molecular weight (600,000 < Mn < 4,500,000 g mol-1 ) and substantial amounts of double bonds along the polymer main chain. Olefinic moieties in ROMP-derived polymers can be converted into hydroxyl, amino, silyl, ester, or carboxylate groups by different means including controlled radical polymerization-based grafting. The underlying concept for the switch in polymerization mechanism, the resulting pre-catalyst requirements, limitations and challenges and the chemistry developed for functionalizing unsaturated polymers are outlined in detail.

Facile synthesis of block copolymers by tandem ROMP and eROP from esters precursors.

In the present study, block copolymers were first synthesized through a tandem ring-opening metathesis polymerization (ROMP) and conventional enzymatic ring-opening polymerization (eROP) from hydroxyl initiator. Furthermore, a novel synthesis route, single-step eROP from ester precursor was successfully developed to synthesize targeted copolymers. The as-prepared polymers were analyzed by NMR, GPC, DSC, and MALDI-TOF-MS. There was no difference in the characteristic peaks of NMR between the end products obtained from these two synthetic routes. The GPC data showed that the copolymer obtained from single-step eROP was similar to the end product obtained from the traditional multistep synthesis method. Afterward, we used model compounds to carry out the conventional eROP and the single-step eROP. Finally, through the kinetic analysis and structural analysis of the resulting product, a reasonable initiation mechanism for this single-step eROP was elucidated.

Tandem Ring-Opening Metathesis / Vinyl Insertion Polymerization-Derived Poly (Olefin)s

The concept for preparing functional, high molecular weight poly(olefin)s via tandem ring-opening metathesis / vinyl insertion polymerization is reviewed. It is based on a reversible α-H-addition/α-H-elimination process occurring in tailor-made catalysts. Copolymerization of ethylene with cyclic olefins with these catalysts yields poly(olefin)s with double bonds in the main chain. These can then be converted into various functional groups. First accomplishments are reported. Particular attention is devoted to the current status of this approach, its limitations and to approaches to overcome these. Keywords: Ring-opening metathesis polymerization (ROMP), Vinyl insertion polymerization (VIP), Olefin, Ethylene, Norborn-2-ene.

Efficient Synthesis of Long-Chain Highly Branched Polymers via One-Pot Tandem Ring-Opening Metathesis Polymerization and Acyclic Diene Metathesis Polymerization

A facile one-pot synthesis of long-chain highly branched polymers (LCHBPs) was accomplished by a tandem ring-opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET) polymerization procedure. A telechelic polymer with two terminal allyloxy groups and many pendent acrylates was first prepared through the first generation Grubbs catalyst-mediated chain transfer ROMP of 7-oxanorborn-5-ene-exo,exo-2,3-dicarboxylic acid bis(2-(acryloyloxy)ethyl) ester in the presence of a symmetrical multifunctional olefin 1,4-diallyloxy-cis-2-butene as chain transfer agent (CTA), and then utilized as an A2B2n-type macromonomer in subsequent ADMET polymerization between allyloxy and acrylate triggered by the most activated second generation Grubbs catalyst, yielding LCHBPs as the reacton time prolonged. The CTA, monomer, macromonomer, and the resulting LCHBPs were characterized by mass spectroscopy, elemental analysis, gel permeation chromatography with multiangle laser light scattering, NMR and matrix-ass...

Hybrid Polymer Particles by Tandem Ring-Opening Metathesis and Atom Transfer Radical Polymerizations in Aqueous Miniemulsion

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTHybrid Polymer Particles by Tandem Ring-Opening Metathesis and Atom Transfer Radical Polymerizations in Aqueous MiniemulsionDamien Quémener, Antoine Bousquet, Valérie Héroguez, and Yves GnanouView Author Information Laboratoire de Chimie des Polymères Organiques, ENSCPB, 16 avenue Pey-Berland, 33607 Pessac, France Cite this: Macromolecules 2006, 39, 17, 5589–5591Publication Date (Web):July 28, 2006Publication History Received18 May 2006Revised19 July 2006Published online28 July 2006Published inissue 1 August 2006https://doi.org/10.1021/ma061118oCopyright © 2006 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views599Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (80 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Copolymers,Emulsions,Organic compounds,Polymer particles,Radical polymerization Get e-Alerts

Ligand manipulation and design for ruthenium metathesis and tandem metathesis-hydrogenation catalysis

Results of investigations into tandem ring-opening metathesis polymerization (ROMP)-hydrogenation are reviewed, in which hydrogen and 3-chloro-3-methyl-1-butyne provide simple chemical toggles to switch between metathesis and hydrogenation chemistry, enabling multiple tandem catalysis in chlorocarbon solvent. In the presence of methanol, hydrogenation of metathesis polymers can be carried out under 1 atm H 2. Issues of ligand design are examined in developing new Ru-diphosphine catalysts with improved selectivity, and an important decomposition pathway is identified for RuCl 2(PP)(CHR) systems (PP=chelating diphosphine).