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Proton-triggered topological transformation in superbase-mediated selective polymerization enables access to ultrahigh-molar-mass cyclic polymers
The selective synthesis of ultrahigh-molar-mass (UHMM) cyclic polymers from direct polymerization is elusive. Using a chemically recyclable polythioester as a model, it has now been shown that a common superbase mediates living linear-chain growth, followed by proton-triggered linear-to-cyclic topological transformation, producing UHMM cyclic polymers with a narrow dispersity.
- Li Zhou
- , Liam T. Reilly
- & Eugene Y.-X. Chen
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| Open AccessMechanically triggered on-demand degradation of polymers synthesized by radical polymerizations
Radical polymerizations yield polymers that cannot easily be degraded. The co-polymerization of cyclobutene-based monomers with conventional vinyl monomers has now been shown to result in co-polymers with cyclobutane mechanophores in their backbone, which facilitate on-demand degradation through a combination of mechanical activation and hydrolysis. This approach offers a promising avenue for the degradation of all-carbon-bond-backbone polymers.
- Peng Liu
- , Sètuhn Jimaja
- & Nico Bruns
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| Open AccessPorphyrin-fused graphene nanoribbons
The insertion of metal atoms and heteroaromatic units provides a way to tune the optical, electronic and magnetic properties of graphene nanoribbons. Now the synthesis of a porphyrin-fused graphene nanoribbon with a narrow bandgap and high charge mobility has been achieved, and this material used to fabricate field-effect and single-electron transistors.
- Qiang Chen
- , Alessandro Lodi
- & Harry L. Anderson
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| Open AccessArtificial cell synthesis using biocatalytic polymerization-induced self-assembly
Enzyme-initiated polymerization-induced self-assembly has been used to generate various biomimetic structures. Now, myoglobin’s activity is used for biocatalytic polymerization-induced self-assembly to generate vesicular artificial cells. As various cargoes can be encapsulated during polymerization, these artificial cells are capable of protein expression and can act as microreactors for distinct enzymatic reactions.
- Andrea Belluati
- , Sètuhn Jimaja
- & Nico Bruns
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Precision native polysaccharides from living polymerization of anhydrosugars
The inability to access well-defined polysaccharides in sufficient quantities has hampered our understanding of their structure–function relationships. Now it has been shown that native precision polysaccharides can be readily prepared via living polymerization of 1,6-anhydrosugars. The obtained polymers display excellent chemical recyclability, suggesting their potential utility as a class of sustainable materials.
- Lianqian Wu
- , Zefeng Zhou
- & Jia Niu
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Growth of single-crystal imine-linked covalent organic frameworks using amphiphilic amino-acid derivatives in water
Covalent organic frameworks (COFs) have remained difficult to grow as single crystals. Now, amphiphilic amino-acid derivatives that assemble in micelles in aqueous solutions have been shown to promote the growth of a variety of imine-bridged COFs into single crystals, in a step-by-step fashion, within their hydrophobic compartment.
- Zhipeng Zhou
- , Lei Zhang
- & Zhikun Zheng
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Nature-inspired methylated polyhydroxybutyrates from C1 and C4 feedstocks
Polyhydroxyalkanoates are potential substitutes for non-degradable polyolefin plastics. Now, it has been shown that structurally related methylated polyhydroxybutyrates, synthesized from carbon monoxide and 2-butenes, can provide a full suite of polyolefin-like polymers. These materials can be recycled or upcycled, and their properties can be easily tuned by varying the cis/trans ratio of the starting materials.
- Zhiyao Zhou
- , Anne M. LaPointe
- & Geoffrey W. Coates
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End-of-life upcycling of polyurethanes using a room temperature, mechanism-based degradation
Extensive crosslinking in thermosetting polymers provides their desirable durability but makes them difficult to recycle. Now acetal-based monomers containing nucleophilic pendant groups have been incorporated into polyurethanes, which are stable in aqueous acid yet degradable at room temperature under organic acidic conditions. The degradation products were upcycled into higher-value, long-lasting materials.
- Ephraim G. Morado
- , Mara L. Paterson
- & Steven C. Zimmerman
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Plasmonic visible–near infrared photothermal activation of olefin metathesis enabling photoresponsive materials
Current strategies for photoinduced olefin metathesis lack wavelength tunability. Now, plasmonic nanoparticles have been used to activate latent ruthenium catalysts, enabling light-induced olefin metathesis in the infrared range with several advantages when compared with conventional heating. Implementing this approach in ring-opening metathesis polymerization resulted in photoresponsive polymer–nanoparticle composites with enhanced mechanical properties.
- Nir Lemcoff
- , Noy B. Nechmad
- & Yossi Weizmann
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A circular polyester platform based on simple gem-disubstituted valerolactones
Geminal disubstitution of cyclic monomers is known to improve the chemical recyclability of their polymers, but usually at the expense of performance properties. Now, geminal disubstitution of a six-membered lactone has been shown to synergistically enable chemical recyclability back to the monomer and enhance the materials performance of the resulting polyesters, with properties that rival or exceed those of polyethylene.
- Xin-Lei Li
- , Ryan W. Clarke
- & Eugene Y.-X. Chen
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Digital micelles of encoded polymeric amphiphiles for direct sequence reading and ex vivo label-free quantification
Identifying and quantifying the biodistribution of synthetic polymeric nanoparticles in biological milieu is crucial for biomedical applications. Now, it has been shown that encoded polymeric amphiphiles with discrete molar masses undergo sequence- and length-dependent self-assembly into precise digital micelles that can be used in direct sequence reading and ex vivo label-free quantification assays.
- Qiangqiang Shi
- , Hao Yin
- & Shiyong Liu
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Photoinduced inverse vulcanization
Inverse vulcanization (IV) generates sulfur-rich functional polymers from elemental sulfur and organic crosslinkers, but the harsh reaction conditions required limit the scope of suitable crosslinkers. Now, a photoinduced IV has been shown to proceed at ambient temperatures, enabling the use of volatile and gaseous alkenes and alkynes as crosslinkers and broadening the range of products.
- Jinhong Jia
- , Jingjiang Liu
- & Zheng-Jun Quan
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Stereocontrolled acyclic diene metathesis polymerization
Polymerization methods that control the cis/trans stereochemistry of repeating alkenes in polyalkenamers remain scarce. Now, an acyclic diene metathesis process has been developed that enables control over the stereochemistry of the polymer backbone. The method harnesses the reactivity of dithiolate Ru carbenes, in combination with cis,cis-diene monomers, to access several classes of polymers with tailored properties.
- Ting-Wei Hsu
- , Samuel J. Kempel
- & Quentin Michaudel
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A two-residue nascent-strand steric gate controls synthesis of 2′-O-methyl- and 2′-O-(2-methoxyethyl)-RNA
Sterically demanding 2′-modified nucleotides used in antisense therapeutics have thus far been challenging to synthesise enzymatically. Now, it has been shown that mutation of two gatekeeper residues in an archaeal DNA polymerase unlocks efficient synthesis of the modified nucleic acid oligomers 2′-O-methyl-RNA and 2′-O-(2-methoxyethyl)-RNA and enables the evolution of 2′-O-methyl-RNA enzymes.
- Niklas Freund
- , Alexander I. Taylor
- & Philipp Holliger
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Scalable and continuous access to pure cyclic polymers enabled by ‘quarantined’ heterogeneous catalysts
Cyclic polymers are topologically interesting and envisioned as a lubricant material, but methods for the scalable synthesis of pure cyclic polymers are currently elusive. Now, a scalable process has been developed by leveraging heterogeneity of the catalysts with the help of compartmentalized custom glassware, namely, a cyclic polymer dispenser.
- Ki-Young Yoon
- , Jinkyung Noh
- & Robert H. Grubbs
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Tunable and recyclable polyesters from CO2 and butadiene
The direct copolymerization of carbon dioxide and commodity olefins has been a long-standing challenge in polymer science. Now, an indirect approach has been developed in which hydrogenated disubstituted valerolactones derived from telomerization of CO2 and butadiene can undergo ring-opening polymerization, yielding chemically recyclable and degradable aliphatic polyesters with high CO2 content.
- Rachel M. Rapagnani
- , Rachel J. Dunscomb
- & Ian A. Tonks
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Sustainable polyesters via direct functionalization of lignocellulosic sugars
Functionalizing an intact carbohydrate core with acetals allows for the dramatically simplified production of a plastic precursor directly during the initial fractionation of non-edible biomass. When polymerized, the rigid and polar carbohydrate core also leads to bioplastics with competitive material and end-of life properties.
- Lorenz P. Manker
- , Graham R. Dick
- & Jeremy S. Luterbacher
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News & Views |
Sustainable and degradable plastics
Plastics that are developed from renewable resources and can be recycled are highly environmentally desirable alternatives to current petroleum-based non-degradable polymers. Now, an effective and robust industrially relevant strategy towards high-performance biomass-derived degradable poly(γ-thiobutyrolactone)s has been developed.
- Sophie M. Guillaume
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Concurrent control over sequence and dispersity in multiblock copolymers
Synthetic approaches that can simultaneously control both polymer sequence and dispersity are difficult to achieve. Now, a switchable RAFT agent that regulates chain transfer activity during controlled radical polymerization has been shown to enable the one-pot synthesis of sequence-controlled multiblocks with on-demand control over dispersity while maintaining high livingness.
- Maria-Nefeli Antonopoulou
- , Richard Whitfield
- & Athina Anastasaki
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Bottlebrush polymers with flexible enantiomeric side chains display differential biological properties
The contributions of chirality and conformation as contributing factors to the biological properties of synthetic nanomaterials remain underexplored. A synthesis of bottlebrush polymers with mirror-image side chains has now been developed and it has been revealed that an interplay between side-chain absolute configuration and flexibility influences the biological properties of these polymers both in vitro and in vivo.
- Hung V.-T. Nguyen
- , Yivan Jiang
- & Jeremiah A. Johnson
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Towards high-performance sustainable polymers via isomerization-driven irreversible ring-opening polymerization of five-membered thionolactones
Five-membered lactones are common in nature and are produced in large quantities from biomass, but a lack of ring strain means that ring-opening polymerization is usually thermodynamically unfavourable at ambient conditions. Now, an irreversible ring-opening polymerization of biomass-derived five-membered thionolactones—driven by S/O isomerization—has been developed, enabling their conversion into sustainable polymers at industrially relevant temperatures.
- Pengjun Yuan
- , Yangyang Sun
- & Miao Hong
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A versatile approach for the synthesis of degradable polymers via controlled ring-opening metathesis copolymerization
Degradable polymers are important for technological applications and sustainability, but they remain difficult to access via ring-opening metathesis polymerization (ROMP). Now, commercial 2,3-dihydrofuran is shown to be an effective ROMP comonomer for various norbornenes. This copolymerization generates new acid-degradable polymers with controlled molecular weights, different functionalities and tunable properties.
- John D. Feist
- , Daniel C. Lee
- & Yan Xia
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News & Views |
From disposable diapers to adhesives
Finding alternative fates for plastics that would otherwise end up in landfills requires innovative chemistry. Now, poly(acrylic acid) from diaper waste has been converted into valuable pressure-sensitive adhesives through an open-loop recycling method that is cost-effective and environmentally competitive.
- Meredith A. Borden
- & Frank A. Leibfarth
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News & Views |
Just a click away
The precisely ordered helical structures of biomacromolecules have long-inspired chemists to create synthetic helical polymers. Now, a new step-growth approach has enabled facile synthesis of helical polymers through the highly efficient sulfur(vi) fluoride exchange click chemistry.
- Cangjie Yang
- & Jia Niu
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News & Views |
Low strain, more gain
Recycling polymers to their monomers would enable a circular polymer economy, but this can be challenging, especially for materials with all-carbon backbones. Now, by lowering the strain of cyclooctene through ring fusion, recyclable polymers with useful physical properties can be made by an olefin-metathesis-based route.
- Yutan Getzler
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Olefin metathesis-based chemically recyclable polymers enabled by fused-ring monomers
Depolymerizable polymers can potentially address challenges in polymer sustainability, but most existing systems lack the useful thermomechanical properties of traditional ones. Now, it has been shown that depolymerizable polymers based on olefin metathesis show good thermal stability as well as versatile mechanical properties and that the monomers used to make them can be prepared from abundant materials.
- Devavrat Sathe
- , Junfeng Zhou
- & Junpeng Wang
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A versatile living polymerization method for aromatic amides
Two phosphine-based reagents can be used to prepare aromatic acid chlorides in the presence of either primary or secondary amines. This approach enables the living polycondensation of aromatic amino acids under mild conditions and can be used to make block copolymers as well as helical aromatic amide foldamers.
- Subhajit Pal
- , Dinh Phuong Trinh Nguyen
- & Andreas F. M. Kilbinger
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Iron-catalysed synthesis and chemical recycling of telechelic 1,3-enchained oligocyclobutanes
Iron-catalysed [2+2] cycloaddition/oligomerization of neat butadiene affords
(1,n′-divinyl)oligocyclobutane —a telechelic, crystalline material consisting of 1,3-enchained cyclobutyl units. This oligocyclobutane can be chemically recycled to pure butadiene using the same iron catalyst employed in its synthesis, demonstrating design principles for next-generation plastic materials that can be returned to pristine monomer.- Megan Mohadjer Beromi
- , C. Rose Kennedy
- & Paul J. Chirik
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Mechanochemical synthesis of an elusive fluorinated polyacetylene
Fluorinated polyacetylene has typically proven to be inaccessible using traditional polymer synthesis, but there is much interest in its predicted properties. Now, a mechanochemical unzipping strategy has succeeded in the synthesis of a gold-coloured, semiconducting fluorinated polyacetylene with improved stability in air compared to polyacetylene.
- Benjamin R. Boswell
- , Carl M. F. Mansson
- & Noah Z. Burns
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Distal conformational locks on ferrocene mechanophores guide reaction pathways for increased mechanochemical reactivity
Metallocenes are attractive mechanophores because they are stable in the absence of force, yet reactive under tension. Now, covalently bridging the two cyclopentadienyl (Cp) ligands of ferrocenes embedded in a polymer has been shown to alter their mechanochemical reactivity, leading to a faster dissociation of the Fe–Cp bond, which occurs through a peeling mechanism rather than a shearing one.
- Yudi Zhang
- , Zi Wang
- & Stephen L. Craig
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Emergence of low-symmetry foldamers from single monomers
The majority of discrete structures obtained by self-assembly possess high symmetry, and thus low complexity: all subunits relate to their neighbours in a similar manner. Now, the spontaneous formation of complex low-symmetry assemblies produced from a single building block has been demonstrated using a systems chemistry approach. The single building block oligomerizes to form specific homomeric cyclic macromolecules that adopt a folded conformation.
- Charalampos G. Pappas
- , Pradeep K. Mandal
- & Sijbren Otto
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Aerobic radical polymerization mediated by microbial metabolism
Oxygen is a potent inhibitor of radical polymerization reactions, but the facultative bacterium Shewanella oneidensis has now been shown to facilitate aerobic radical polymerizations by first consuming dissolved oxygen and then directing extracellular electron flux to a metal catalyst. Aerobic polymerization activity is dependent on the S. oneidensis genotype and can be initiated using lyophilized or spent cells.
- Gang Fan
- , Austin J. Graham
- & Benjamin K. Keitz
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News & Views |
New stereocontrol on the block
It is crucial to replace fossil fuel-based plastics with biodegradable ones that are made from renewable sources. Now, a new generation of bioplastics has been prepared through the stereoselective polymerization of diastereomeric monomers — a synthetic approach that allows tuning of the materials’ toughness, ductility and melting point.
- Sonja Herres-Pawlis
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Review Article |
Covalent on-surface polymerization
Growing polymers directly on surfaces has emerged as a powerful tool because it can provide a route to otherwise inaccessible structures such as defect-free linear chains, graphene nanoribbons and two-dimensional networks. This Review Article describes general principles and key aspects of this method from the perspectives of surface science and polymer chemistry.
- Leonhard Grill
- & Stefan Hecht
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Tailored silyl ether monomers enable backbone-degradable polynorbornene-based linear, bottlebrush and star copolymers through ROMP
Ring-opening metathesis polymerization of norbornene-based (macro)monomers produces macromolecules with diverse compositions and complex architectures that cannot be degraded easily. Now, it has been shown that a class of eight-membered cyclic bifunctional silyl ether-based monomers copolymerize efficiently with norbornene-based (macro)monomers, providing a range of copolymers with tunable degradability under mildly acidic aqueous conditions.
- Peyton Shieh
- , Hung V.-T. Nguyen
- & Jeremiah A. Johnson
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On-water surface synthesis of crystalline, few-layer two-dimensional polymers assisted by surfactant monolayers
It is difficult to prepare 2D polymers that are crystalline over large areas. Now, few-layer 2D polyimides and polyamides with good crystallinity on the micrometre scale have been synthesized on a water surface. A surfactant monolayer is used to organize amine monomers before their polymerization with anhydride moieties.
- Kejun Liu
- , Haoyuan Qi
- & Xinliang Feng
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Closed-loop recycling of plastics enabled by dynamic covalent diketoenamine bonds
It is difficult to recover materials for re-manufacturing and re-use from plastics that are compounded with colourants, fillers and flame retardants. Now, it has been shown that alternative plastics based on dynamic covalent poly(diketoenamine)s depolymerize in strong aqueous acids and enable triketone and amine monomers to be isolated and upcycled into new plastics.
- Peter R. Christensen
- , Angelique M. Scheuermann
- & Brett A. Helms
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Sequence-defined multifunctional polyethers via liquid-phase synthesis with molecular sieving
The creation of a viable technology that enables precise control over the monomer sequence in synthetic polymers remains a significant challenge. High-purity sequence-defined polyethers with readily tailored side-chain functionalities have now been made through liquid-phase iterative synthesis combined with size-exclusion molecular sieving and real-time monitoring.
- Ruijiao Dong
- , Ruiyi Liu
- & Andrew G. Livingston
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Micrometre-long covalent organic fibres by photoinitiated chain-growth radical polymerization on an alkali-halide surface
On-surface polymerization is a promising technique to prepare organic functional nanomaterials, but it has remained difficult to carry out on insulating surfaces. Now, the photoinitiated radical polymerization of dimaleimide on KCl, initiated from a two-dimensional gas phase and guided by molecule–substrate interactions, has led to polymer fibres up to 1 μm long.
- Franck Para
- , Franck Bocquet
- & Matthew B. Watkins
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News & Views |
Gaining control
Using infrared light to control the outcome of a chemical reaction is problematic in solution because of numerous interactions and non-specific sample heating. Now, condensed-phase results showing the vibrational enhancement of an otherwise thermally driven reaction may reinvigorate discussion of the practical applications of vibrational control.
- Amanda S. Case
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Article |
Engineered modular biomaterial logic gates for environmentally triggered therapeutic delivery
Biomaterials that respond to precise combinations of environmental cues represent an important technology for tissue engineering and next-generation drug delivery systems. Now, a modular framework to programme material degradation following Boolean logic has been demonstrated by specifying the molecular architecture and connectivity of orthogonal stimuli-labile moieties within hydrogel cross-linkers.
- Barry A. Badeau
- , Michael P. Comerford
- & Cole A. DeForest
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Acceleration of a ground-state reaction by selective femtosecond-infrared-laser-pulse excitation
A practical realization of selective IR-driven reaction-rate control has been hampered by competing processes leading to sample heating. Now, the acceleration of a bimolecular ground-state reaction in solution using the IR excitation of a vibration connected to the reaction coordinate is demonstrated. The behaviour is monitored and understood using a combination of femtosecond IR-pump IR-probe spectroscopy and theoretical calculations.
- Till Stensitzki
- , Yang Yang
- & Karsten Heyne
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Thermally bisignate supramolecular polymerization
An attractive feature of supramolecular polymers is their reversibility — they typically depolymerize upon heating. Now, in the presence of a scavenger molecule, a metalloporphyrin derivative bearing eight amide-containing side chains has been shown to undergo supramolecular polymerization on heating as well as cooling through π-stacking and multivalent hydrogen-bonding interactions.
- Kotagiri Venkata Rao
- , Daigo Miyajima
- & Takuzo Aida
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Bifluoride-catalysed sulfur(VI) fluoride exchange reaction for the synthesis of polysulfates and polysulfonates
Both click chemistry and polymer synthesis require reliable transformations with high selectivity, efficiency and fidelity. Now, bifluoride salts can be used as powerful catalysts for the sufur(VI) fluoride exchange (SuFEx) click reaction and they are applied to the synthesis of polysulfates and polysulfonates in a practical and scalable manner.
- Bing Gao
- , Linda Zhang
- & K. Barry Sharpless
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Anionic silicate organic frameworks constructed from hexacoordinate silicon centres
Hexacoordinate silicon is seen often in molecular compounds, but very rarely in crystalline silicate materials. Now, reversible Si–O chemistry has been used to assemble octahedral dianionic SiO6 building units and anthracene derivatives into crystalline microporous silicate organic frameworks that share characteristics of both covalent organic frameworks and inorganic zeolites.
- Jérôme Roeser
- , Dragica Prill
- & Arne Thomas
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Main-chain metallopolymers at the static–dynamic boundary based on nickelocene
Main-chain polymetallocenes are typically static in nature due to strong metal–ligand bonding. Now, it has been shown that such polymers based on nickelocene are dynamic due to weaker nickel–cyclopentadienyl interactions, and at low concentration or at elevated temperature, depolymerization to the moderately strained monomer occurs.
- Rebecca A. Musgrave
- , Andrew D. Russell
- & Ian Manners
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Macromolecular metamorphosis via stimulus-induced transformations of polymer architecture
Many properties of polymers are dictated by topology. However, the topology of a macromolecule is typically a static feature after synthesis. Now, an approach to dynamic and transformable macromolecular architecture has been developed. When triggered by an external stimulus, macromolecular topology can be triggered to transform via thermodynamic control.
- Hao Sun
- , Christopher P. Kabb
- & Brent S. Sumerlin
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Cooperative polymerization of α-helices induced by macromolecular architecture
The secondary and tertiary structure of a protein has profound implications on function and catalysis. Now, both the secondary and tertiary structures of a synthetic polymer have been utilized to catalyse the polymerization of N-carboxyanhydrides. Both the folding of the resulting polypeptides into α-helices and their macromolecular organization dramatically enhance the polymerization rate.
- Ryan Baumgartner
- , Hailin Fu
- & Jianjun Cheng
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Engineering live cell surfaces with functional polymers via cytocompatible controlled radical polymerization
A cytocompatible controlled radical polymerization method has now been developed that initiates polymer synthesis directly on the surface of living cells. This method achieves significantly enhanced polymer grafting and enables active manipulation of cellular phenotypes.
- Jia Niu
- , David J. Lunn
- & Craig J. Hawker