Aqueous Ring-opening Metathesis Polymerization Research Articles

Monomer Emulsified Aqueous Ring-Opening Metathesis Polymerization (ME-ROMP) for the Synthesis of Water-Soluble Molecular Bottlebrushes with a Precise Structure

Monomer Emulsified Aqueous Ring-Opening Metathesis Polymerization (ME-ROMP) for the Synthesis of Water-Soluble Molecular Bottlebrushes with a Precise Structure

Ultrafast Monomer Emulsified Aqueous Ring-Opening Metathesis Polymerization for the Synthesis of Water-Soluble Polynorbornenes with Precise Structure.

Ring-opening metathesis polymerization (ROMP) in an aqueous medium provides an important environmentally friendly platform for the preparation of water-soluble polymeric materials. However, it is challenging to keep high synthetic efficacy and good control over molecular weight and distribution due to the inevitable catalyst decomposition in an aqueous medium. To meet this challenge, we propose a facile monomer emulsified aqueous ROMP (ME-ROMP) by injecting a tiny amount of a CH2Cl2 solution of the Grubbs' third-generation catalyst (G3) into the aqueous solution of norbornene (NB) monomers without deoxygenation. Driven by the minimization of interfacial tension, the water-soluble monomers could serve as surfactants with hydrophobic NB moieties inserted into the CH2Cl2 droplets of G3, leading to the significantly suppressed catalyst decomposition and accelerated polymerization. The ME-ROMP is confirmed to be living with an ultrafast polymerization rate, near quantitative initiation and monomer conversion, for the highly efficient and ultrafast synthesis of well-defined water-soluble polynorbornenes with various compositions and architectures.

Water-soluble polyphosphonate-based bottlebrush copolymers via aqueous ring-opening metathesis polymerization.

Ring-opening metathesis polymerization (ROMP) is a versatile method for synthesizing complex macromolecules from various functional monomers. In this work, we report the synthesis of water-soluble and degradable bottlebrush polymers, based on polyphosphoesters (PPEs) via ROMP. First, PPE-macromonomers were synthesized via organocatalytic anionic ring-opening polymerization of 2-ethyl-2-oxo-1,3,2-dioxaphospholane using N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide as the initiator and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the catalyst. The resulting norbornene-based macromonomers had degrees of polymerization (DPn) ranging from 25 to 243 and narrow molar mass dispersity (Đ ≤ 1.10). Subsequently, these macromonomers were used in ROMP with the Grubbs 3rd-generation bispyridyl complex (Ru-G3) to produce a library of well-defined bottlebrush polymers. The ROMP was carried out either in dioxane or in aqueous conditions, resulting in well-defined and water-soluble bottlebrush PPEs. Furthermore, a two-step protocol was employed to synthesize double hydrophilic diblock bottlebrush copolymers via ROMP in water at neutral pH-values. This general protocol enabled the direct combination of PPEs with ROMP to synthesize well-defined bottlebrush polymers and block copolymers in water. Degradation of the PPE side chains was proven resulting in low molar mass degradation products only. The biocompatible and biodegradable nature of PPEs makes this pathway promising for designing novel biomedical drug carriers or viscosity modifiers, as well as many other potential applications.

It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH.

Aqueous ring-opening metathesis polymerization (ROMP) is a powerful tool for polymer synthesis under environmentally friendly conditions, functionalization of biomacromolecules, and preparation of polymeric nanoparticles via ROMP-induced self-assembly (ROMPISA). Although new water-soluble Ru-based metathesis catalysts have been developed and evaluated for their efficiency in mediating cross metathesis (CM) and ring-closing metathesis (RCM) reactions, little is known with regards to their catalytic activity and stability during aqueous ROMP. Here, we investigate the influence of solution pH, the presence of salt additives, and catalyst loading on ROMP monomer conversion and catalyst lifetime. We find that ROMP in aqueous media is particularly sensitive to chloride ion concentration and propose that this sensitivity originates from chloride ligand displacement by hydroxide or H2O at the Ru center, which reversibly generates an unstable and metathesis inactive complex. The formation of this Ru-(OH)n complex not only reduces monomer conversion and catalyst lifetime but also influences polymer microstructure. However, we find that the addition of chloride salts dramatically improves ROMP conversion and control. By carrying out aqueous ROMP in the presence of various chloride sources such as NaCl, KCl, or tetrabutylammonium chloride, we show that diblock copolymers can be readily synthesized via ROMPISA in solutions with high concentrations of neutral H2O (i.e., 90 v/v%) and relatively low concentrations of catalyst (i.e., 1 mol %). The capability to conduct aqueous ROMP at neutral pH is anticipated to enable new research avenues, particularly for applications in biological media, where the unique characteristics of ROMP provide distinct advantages over other polymerization strategies.

Optimization of Ring-Opening Metathesis Polymerization (ROMP) under Physiologically Relevant Conditions.

Ring opening metathesis polymerization (ROMP) is widely considered an excellent living polymerization technique that proceeds rapidly under ambient conditions and is highly functional group tolerant when performed in organic solvents. However, achieving the same level of success in aqueous media has proved to be challenging, often requiring an organic co-solvent or a very low pH to obtain fast initiation and high monomer conversion. The ability to efficiently conduct ROMP under neutral pH aqueous conditions would mark an important step towards utilizing aqueous ROMP with acid-sensitive functional groups or within a biological setting. Herein we describe our efforts to optimize ROMP in an aqueous environment under neutral pH conditions. Specifically, we found that the presence of excess chloride in solution as well as relatively small changes in pH near physiological conditions have a profound effect on molecular weight control, polymerization rate and overall monomer conversion. Additionally, we have applied our optimized conditions to polymerize a broad scope of water-soluble monomers and used this methodology to produce nanostructures via ring opening metathesis polymerization induced self-assembly (ROMPISA) under neutral pH aqueous conditions.

An insight into the beginning stage of the aqueous ring opening metathesis polymerization of exo,exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid with RuIII compounds: the consumption of RuIII species in the presence of carboxylic acids monitored by ESR spectroscopy

The presence of paramagnetic species in the aqueous ring opening metathesis polymerizations of the exo,exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid monomer with RuCl3 and K2[RuCl5H2O] compounds was studied using ESR techniques. It was observed that the intensities of the RuIII signals in the ESR spectra decrease on the time scale of the induction period so that the ROMP can take place. The intensity of the RuIII signal almost disappeared 50 min after reacting with K2[RuCl5H2O] and after 100 min in the case of RuCl3. Reactions of the cis-[Ru(NH3)4(H2O)2](tfms)3 and [Ru(NH3)5H2O](tfms)3 complexes with the monomer and different organic compounds representing the organic functions in the monomer (furan, norbornene, but-2-ene-1,4-diol and formic, acetic, oxalic and maleic acids) were also monitored by ESR and UV/vis spectra. It was deduced that the organic acids provide the disappearance of the RuIII signal. The proton NMR relaxation times of the residual water in D2O for reactions with oxalic acid suggested that the presence of paramagnetic ions in the solution decreases along with the disappearance of the ESR signal for RuIII. It was suggested that diamagnetic Ru species were indeed produced in the medium.

A Neutral, Water‐Soluble Olefin Metathesis Catalyst Based on an N‐Heterocyclic Carbene Ligand.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A neutral, water-soluble olefin metathesis catalyst based on an N-heterocyclic carbene ligand

A water-soluble ruthenium-based olefin metathesis catalyst supported by a poly(ethylene glycol) conjugated N-heterocyclic carbene ligand is reported. The catalyst displays greater activity in aqueous ring-opening metathesis polymerization (ROMP) reactions than previously reported water-soluble metathesis catalysts.

Thermal- and photoinduced ring-opening metathesis polymerization (ROMP)/(PROMP): an efficient tool in polymer chemistry

Properties and applications of newly developed homogeneous ring-opening metathesis polymerization catalysts as well as photoinduced ring-opening metathesis polymerization catalysts are discussed. It is shown that simple alkyl complexes, e.g. [W(NPh)(CH 2SiMe 3) 3Cl] as well as [Ru(arene) 2] 2+ or [Ru(NC–R) 6] 2+ complexes act as one-component Photo-ROMP initiators. Catalysts with good thermal latency are described for both classes. High quantum yields are observed for the photochemically induced solvation of Ru(II) complexes. Polymer structure and kinetic aspects of the reaction are consistent with [Ru(solvent) 6] 2+ acting as the catalytically active species. The mechanism of aqueous ROMP with Ru(II) salts is discussed, which differs considerably from the classical ROMP reaction with Schrock-type catalysts in the sense that it is a chain reaction and not a living polymerization. Homo- and copolymers using exo-oxa-norbornene-carboximide ester derivatives were prepared with the ROMP technology and used, inter alia, to formulate very sensitive positive tone high-resolution microresists.

Neoglycopolymers produced by aqueous ring-opening metathesis polymerization: decreasing saccharide density increases activity

Non-natural carbohydrate-bearing polymers are emerging as important materials for the investigation of multivalent carbohydrate-protein interactions. In the present study, neoglycopolymers were generated via aqueous ring-opening metathesis polymerizations. A procedure employing a ruthenium catalyst, preformed by treating a small quantity of the monomer with RuCl 3, reduced metal contamination in the products. To examine the effect of sugar residue density on polymer function, materials bearing one or two sugar ligands per repeat unit were synthesized. These polymers were tested for their ability to inhibit the erythrocyte agglutinating activity of the carbohydrate-binding protein, concanavalin A. The polymers with lower sugar density were found to be more potent inhibitors than polymers with higher density, a result that can be rationalized by analysis of the protein and polymer structures.

Recent Developments in Ring-Opening Metathesis Polymerization (ROMP)

Properties and applications of newly developed homogeneous Ring-Opening Metathesis Polymerization catalysts as well as Photo-induced Ring-Opening Metathesis Polymerization catalysts are discussed. In contrast to well-defined, one-component metal-carbene catalysts, the aqueous ROMP with simple RuII salts is a chain reaction and not a living polymerization. One-component Photo-ROMP initiators were developed with good thermal latency and are either based on early-transition-metal alkyl complexes or on [Ru(arene)2]2+ complexes. Mechanistic aspects of the photochemically induced solvation of RuII complexes are presented.

Recognition Specificity of Neoglycopolymers Prepared by Ring-Opening Metathesis Polymerization

Recognition Specificity of Neoglycopolymers Prepared by Ring-Opening Metathesis Polymerization

Synthesis of Cell Agglutination Inhibitors by Aqueous Ring-Opening Metathesis Polymerization

Synthesis of Cell Agglutination Inhibitors by Aqueous Ring-Opening Metathesis Polymerization

Chain transfer during the aqueous ring-opening metathesis polymerization of 7-oxanorbornene derivatives

Ring-opening metathesis polymerization (ROMP) of exo,exo-5,6-bis(methoxymethyl)-1-oxabicyclo[2.2.1]hept-2-ene (3) catalyzed by Ru II (H 2 O) 6 (tos) 2 (tos= p-toluenesulfonate) (1) in the presence of terminal acyclic olefins such as 3-buten-1-ol and methyl acrylate affords low molecular weight polymeric materials. Analysis of these oligomer samples by one- and two-dimensional 1 H NMR spectroscopy identifies them as resulting from a true metathesis chain transfer mechanism. These data and the identification of the ring-opened monomer units with alkylidene end groups corresponding to the acyclic chain transfer agent by high resolution mass spectrometry confirm this study as the first example of metathesis of an acyclic olefin by 1

Aqueous ring‐opening metathesis polymerization of exo‐7‐oxabicyclo [2.2.1] hept‐5‐ene‐2,3‐dicarboximide

AbstractThe aqueous ring‐opening metathesis polymerization of the exo‐Diels‐Alder adduct of furan and maleimide was accomplished using an “activated Ruthenium” catalyst present in the supernatant of a RuCl3‐catalyzed aqueous polymerization of furan‐dimethylacetylene dicarboxylate adduct. The polymer was characterized by solution 1H− and 13C‐NMR, IR, DSC, and viscometry. Characterization revealed an intact imide group and the possibility of high‐temperature applications. © 1993 John Wiley & Sons, Inc.

Aqueous ring-opening metathesis polymerization and copolymerization of 2,3-dicarboxylic acid anhydride, 2,3-bis(methoxymethyl) and 2,3-dicarboxylic acid mono-methyl ester derivatives of 7-oxanorbornene

The aqueous ring-opening metathesis polymerization of 2,3-dicarboxylic acid anhydride (I), 2,3-bis(methoxymethyl) (II) and 2,3-dicarboxylic acid mono-methyl ester (III) derivatives of 7-oxanorbornene was explored. Reactions were catalysed by commercial ruthenium trichloride with aqueous ethanol or water as solvent. The anhydride ring opened during polymerization of I. The rate of polymerization of III exceeded that of II. The copolymerization of II and III was investigated for the case of monomers either mixed initially or added sequentially. Solubility data indicated that statistical copolymers were produced in both cases.

The aqueous ring-opening metathesis polymerization of 7-oxa-norbornene-2,3-dicarboxylic acid dimethyl ester and norbornene with Ru catalysts

7-Oxa-norbornene-2,3-dicarboxylic acid dimethyl ester ( exo, exo-7-oxa-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid dimethyl ester) was polymerized by ring-opening methathesis polymerization (ROMP) using various ruthenium catalysts and various aqueous solvents. The influence of solvent on induction time, molecular weight and yield of the product polymer is discussed. Norbornene (bicyclo[2.2.1]hept-2-ene), regarded as quite unreactive in aqueous solvents until now, gave copolymers with this oxa-monomer in good yield.

Aqueous ring-opening metathesis polymerization of carboximide-functionalized 7-oxanorbornenes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAqueous ring-opening metathesis polymerization of carboximide-functionalized 7-oxanorbornenesMarc A. Hillmyer, Christine Lepetit, Dominic V. McGrath, Bruce M. Novak, and Robert H. GrubbsCite this: Macromolecules 1992, 25, 13, 3345–3350Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://doi.org/10.1021/ma00039a004RIGHTS & PERMISSIONSArticle Views924Altmetric-Citations86LEARN 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 PDF (752 KB) Get e-Alerts Get e-Alerts

Aqueous ring-opening metathesis polymerizations of heteropolycyclic carboxylic acids with transition-metal chlorides

exo,exo-7-Oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid was polymerized by aqueous ring-opening metathesis polymerization using the trichlorides of ruthenium and osmium as precursors to the initiating and chain propagating species to yield poly(2,5-[3,4-bis(carboxylic acid)furanylene]vinylene)s. Ruthenium-derived initiators gave polymers with 60% of cis-vinylenes whereas polymerization initiated by osmium compounds was irreproducible, giving products with either 65 or 95% cis-vinylenes. The inclusion of acrylic acid or maleic acid in the reaction mixture caused a marked reduction in the time to precipitation of polymer and the ultimate yield. cis-But-2-ene-1,4-diol was found to affect the time to precipitation of polymer in a similar manner without a reduction in yield and allowed control of the polymer molecular weight over the range M n = 10 5 to 7 × 10 2 with respect to poly(ethylene oxide) standards.

Catalytic organometallic chemistry in water: the aqueous ring-opening metathesis polymerization of 7-oxanorbornene derivatives

Catalytic organometallic chemistry in water: the aqueous ring-opening metathesis polymerization of 7-oxanorbornene derivatives