Featured
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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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News & Views |
Mimicking mussel mechanics
Gluing materials together underwater is a mighty challenge faced — and overcome — by mussels. It requires good adhesion and cohesion. Molecular-level mechanical measurements have now shown that cation–π interactions provide surprisingly strong cohesive abilities.
- Henrik Birkedal
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A polymer nanoparticle with engineered affinity for a vascular endothelial growth factor (VEGF165)
Abiotic hydrogel polymer nanoparticles with affinity for a key vascular endothelial growth factor (VEGF165) have now been developed. This high-protein affinity was engineered by carefully controlling the amount and the substitution pattern of sulfated N-acetylglucosamines and the inclusion of a hydrophobic group in the monomer.
- Hiroyuki Koide
- , Keiichi Yoshimatsu
- & Kenneth J. Shea
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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
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A two-dimensional conjugated aromatic polymer via C–C coupling reaction
The synthesis of well-defined planar polymers presents a significant challenge for chemists seeking to investigate their potential for use in emerging technologies. Now, a two-dimensional conjugated aromatic polymer has been synthesized via endogenous solid-state polymerization of pre-arranged monomers, and its performance as an organic anode in an ambient temperature sodium cell tested.
- Wei Liu
- , Xin Luo
- & Kian Ping Loh
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Mechanically controlled radical polymerization initiated by ultrasound
Mechanochemically controlled polymerization is rare in polymer chemistry. Now, it has been shown that mechanical force can initiate and control the polymerization of an acrylate monomer. Piezochemical reduction of a copper(II) precursor using mechanical agitation of piezoelectric nanoparticles generates the polymerization activator required for controlled radical polymerization.
- Hemakesh Mohapatra
- , Maya Kleiman
- & Aaron Palmer Esser-Kahn
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Review Article |
Materials and methods for delivery of biological drugs
Biological drugs can offer high potency and selectivity; however, this class of therapeutics often shows poor stability upon oral administration and during subsequent circulation. This Review highlights the materials and methods used to deliver biological drugs, and discusses how these approaches can improve their pharmacokinetics.
- Alexander N. Zelikin
- , Carsten Ehrhardt
- & Anne Marie Healy
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Sequence-controlled methacrylic multiblock copolymers via sulfur-free RAFT emulsion polymerization
Achieving sequence control in a synthetic polymer is more challenging and time consuming than it is for biopolymers. Now, it has been shown that the synthesis of sequence-controlled multiblock copolymers can be carried out via emulsion polymerization. This approach is environmentally friendly and yields complex multiblock materials with low dispersity and high yields.
- Nikolaos G. Engelis
- , Athina Anastasaki
- & David M. Haddleton
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Photoswitching of glass transition temperatures of azobenzene-containing polymers induces reversible solid-to-liquid transitions
Reversibly inducing solid-to-liquid transitions of polymers at room temperature represents a challenge for enhanced processability and applications of polymers. Now, three azopolymers have been shown to exhibit photoswitchable glass transition temperatures, resulting in reversible solid-to-liquid transitions. Light exposure can heal cracks in hard azopolymers, reduce surface roughness of azopolymer films and control azopolymer adhesion.
- Hongwei Zhou
- , Changguo Xue
- & Si Wu
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Homochiral polymerization-driven selective growth of graphene nanoribbons
Metal surfaces have been believed to be catalytic, but the mechanism of catalysis is unknown. Now, graphene nanoribbons (GNRs) can be grown on Au(111) from a ‘Z-bar-linkage' precursor through a conformation-controlled mechanism. Chemical vapour deposition of precursors adopting a chiral conformation produced homochiral polymers, which are dehydrogenated to form GNRs.
- Hiroshi Sakaguchi
- , Shaotang Song
- & Takahiro Nakae
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Fast and selective ring-opening polymerizations by alkoxides and thioureas
By simply deprotonating a neutral hydrogen-bond donor thiourea it is possible to generate a class of highly efficient and tunable thioimidates that can simultaneously activate a pro-nucleophile and an electrophile. These bifunctional thioimidates exhibit fast kinetics and high selectivity for ring-opening polymerizations of cyclic lactones and carbonates.
- Xiangyi Zhang
- , Gavin O. Jones
- & Robert M. Waymouth
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Membraneless organelles can melt nucleic acid duplexes and act as biomolecular filters
Membraneless organelles form as liquid droplets inside cells. These bodies are effectively a separate organic phase, with unique biochemical properties. Now, the solvent interior of membraneless organelles has been shown to have a significant effect on the properties and structure of biomolecules. In addition to selectively partitioning and trafficking proteins, they can melt DNA without using ATP.
- Timothy J. Nott
- , Timothy D. Craggs
- & Andrew J. Baldwin
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Cyclic polymers from alkynes
Cyclic polymers are an area of significant interest, but understanding the potential of these macrocycles has been difficult because of challenges in their synthesis and characterization. It has now been shown that a tungsten catalyst featuring a tetraanionic pincer ligand can rapidly polymerize alkynes to form conjugated macrocycles in high yield.
- Christopher D. Roland
- , Hong Li
- & Adam S. Veige
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Sequence-defined bioactive macrocycles via an acid-catalysed cascade reaction
Macrocyclic oligomers are a unique structural class of compounds in which the ring size and structure can be tuned through the precise control of the primary sequence. Now, it has been shown that oligothioetheramide (oligoTEA) macrocycles can be synthesized using a one-pot acid-catalysed cascade reaction. Preliminary results indicate that cationic oligoTEAs are promising bactericidal agents.
- Mintu Porel
- , Dana N. Thornlow
- & Christopher A. Alabi
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Fast response dry-type artificial molecular muscles with [c2]daisy chains
Photoresponsive wet- and dry-type actuators can be built up from rotaxane-like structures through the polycondensation of four-armed polyethylene glycols with [c2]daisy chains comprised of cyclodextrin rings and azobenzene side chains. The response of the dry-type (xerogel) actuator to UV light was found to be more than 10,000 times faster than the wet-type (hydrogel) actuator.
- Kazuhisa Iwaso
- , Yoshinori Takashima
- & Akira Harada
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A highly stretchable autonomous self-healing elastomer
Polymers that are both elastic and self-healing are desirable for a variety of applications, but often rely on hydrogen bonding which makes them moisture-sensitive. Now, by incorporating metal–ligand interactions with different bond strengths into flexible polymer backbones, an elastomer has been devised that combines high stretchability and high dielectric strength with autonomous self-healing and mechanical actuation capabilities.
- Cheng-Hui Li
- , Chao Wang
- & Zhenan Bao
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An autonomous molecular assembler for programmable chemical synthesis
Molecular machines that assemble polymers in a programmed sequence are fundamental to life. Now, synthetic machinery built from DNA has been used to execute a molecular program that produces peptides, or olefin oligomers, with a defined sequence. The oligomeric product is linked to a double-stranded DNA product that records the sequence of reactions that were executed.
- Wenjing Meng
- , Richard A. Muscat
- & Andrew J. Turberfield
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News & Views |
Sweet fullerenes vanquish viruses
Fullerene-based dendritic structures coated with 120 sugars can be made in high yields in a relatively short sequence of reactions. The mannosylated compound is shown to inhibit Ebola infection in cells more efficiently than monofullerene-based glycoclusters.
- Sébastien Vidal
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News & Views |
To react the impossible ring
γ-Butyrolactone is a biomass-derived cyclic ester that is commonly thought to be non-polymerizable. Now, exploiting the thermodynamics of polymer formation and careful control of the reaction conditions has made this possible leading to high-molecular-weight products and control of polymer topology.
- Dominic Myers
- , Anish Cyriac
- & Charlotte K. Williams
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A threading receptor for polysaccharides
A synthetic receptor has been designed to form pseudorotaxanes and polypseudorotaxanes with oligo/polysaccharides in water. Target substrates have all-equatorial substitution patterns, and include cellulose, cellodextrins and the cationic polysaccharide chitosan. The results suggest an approach to dissolving these polysaccharides under mild conditions and could prove useful for processing these abundant renewable resources.
- Tiddo J. Mooibroek
- , Juan M. Casas-Solvas
- & Anthony P. Davis
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Completely recyclable biopolymers with linear and cyclic topologies via ring-opening polymerization of γ-butyrolactone
Bio-derived γ-butyrolactone (γ-BL) is commonly referred to as ‘non-polymerizable’ due to its low strain energy. Now it has been shown that ring-opening polymerization of γ-BL can in fact proceed to high conversions under ambient pressure with a suitable catalyst, producing high-molecular-weight polymers with controlled topologies and complete recyclability.
- Miao Hong
- & Eugene Y.-X. Chen
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Highly branched and loop-rich gels via formation of metal–organic cages linked by polymers
Gels formed by metal–ligand coordination typically consist of single metal ions linked together by polymer chains. Now, metal–organic cages have been used as junctions instead. A gel was prepared that features a large number of polymer chains at each junction, including loops that further serve to functionalize the material.
- Aleksandr V. Zhukhovitskiy
- , Mingjiang Zhong
- & Jeremiah A. Johnson
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News & Views |
Remote control for self-assembly
A patterned, spatially resolved gel has now been devised. The two-component gel is formed by sequential assembly of two independent networks of fibres, and the subsequent selective removal of one network by irradiation.
- Haridas Kar
- & Suhrit Ghosh
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Review Article |
Degradable vinyl polymers for biomedical applications
Vinyl polymers are appealing materials owing to their ease of synthesis and broad diversity. Their carbon–carbon backbones resist degradation, however, which limits the applications for which they can be used. This Review Article considers the most promising approaches to the design of degradable vinyl polymers and discusses the potential of these materials for biomedical applications.
- Vianney Delplace
- & Julien Nicolas
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Stable, crystalline, porous, covalent organic frameworks as a platform for chiral organocatalysts
Covalent organic frameworks (COFs) feature periodic layers and ordered pores that make them promising for applications in catalysis, but they typically suffer from poor stability. Now, adding methoxy groups to its pore walls has been shown to strengthen a COF's interlayer interactions, resulting in a stable, crystalline, porous material that can be further converted into chiral organocatalysts.
- Hong Xu
- , Jia Gao
- & Donglin Jiang
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Iterative exponential growth of stereo- and sequence-controlled polymers
Regioselective epoxide opening of an enantiopure epoxy–alkyne results in the stereospecific introduction of functional side-chains into growing macromolecules. This process—in combination with 'click' chemistry and orthogonal deprotection of terminal alkynes—underpins an iterative exponential growth methodology that enables the efficient synthesis of >6-kDa stereo- and sequence-controlled polymers.
- Jonathan C. Barnes
- , Deborah J. C. Ehrlich
- & Jeremiah A. Johnson
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Structure of a PEGylated protein reveals a highly porous double-helical assembly
Protein PEGylation is routinely used to produce molecules with improved pharmacokinetic properties. However, despite their importance, the structure of PEGylated proteins has remained elusive. Now, the first crystal structure of a model β-sheet protein modified with a single PEG chain has been reported. NMR spectroscopy data indicates that the protein and PEG behave as independent domains.
- Giada Cattani
- , Lutz Vogeley
- & Peter B. Crowley
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Catalytic living ring-opening metathesis polymerization
Ring-opening metathesis polymerization (ROMP) offers good control over dispersity, but the requirement of one initiator per chain can be expensive and problematic for purification. Now, a reversible cyclohexenyl-containing chain-transfer agent is described, thus allowing a catalytic living ROMP process to produce narrow dispersity polymers and block copolymers.
- Amit A. Nagarkar
- & Andreas F. M. Kilbinger
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News & Views |
Enzyme activity with a twist
A supramolecular polymer comprising stacked artificial chromophores to which zinc(II) complexes are appended is able to respond to enzymatic hydrolysis in aqueous solution. The assembly of molecules can twist reversibly and quickly in response to changes in the type of adenosine phosphate present.
- David B. Amabilino
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News & Views |
3D frameworks from 3D printers
High-throughput screening of solvothermal crystallization conditions for MOFs and other solids may receive a boost from the application of 3D printing techniques to low-cost, disposable pressure vessels.
- Ian D. Williams
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News & Views |
Served on a nanoplate
Self-assembled cylinders can generally be extended only from their ends — growth that is considered to be 'one-dimensional'. Now, platelet-like structures with controlled size and composition have been constructed by growth in two dimensions of self-assembled structures, starting from crystallite seed micelles.
- Chunhua Cai
- & Jiaping Lin
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Tailored hierarchical micelle architectures using living crystallization-driven self-assembly in two dimensions
Self-assembly is commonly used to construct complex nanostructures from soft matter. Now, using the living crystallization-driven self-assembly approach, controlled nanostructure growth in both one and two dimensions has been achieved. Uniform lenticular multiblock platelets, as well as hierarchical structures analogous to nanoscale single- and double-headed arrows and spears have been prepared with controlled sizes in two dimensions.
- Zachary M. Hudson
- , Charlotte E. Boott
- & Ian Manners
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Triazolinediones enable ultrafast and reversible click chemistry for the design of dynamic polymer systems
Macromolecular functionalization and linking are often facilitated by using ‘click’ chemistries. Now, triazolinediones have been used in ultrafast click reactions under additive-free, ambient conditions for polymer conjugation. Clicking to indoles gives an adduct that is dynamic at elevated temperatures, which produces properties such as polymer-network healing, reshaping and recycling.
- Stijn Billiet
- , Kevin De Bruycker
- & Filip E. Du Prez
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News & Views |
Crystallized creations in 2D
Two reports demonstrate that with the right molecules and the right crystalline arrangement, it is not only possible to create two-dimensional crystals, but also to separate them into single-molecule-thick sheets — so-called two-dimensional polymers.
- Neil R. Champness
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Gram-scale synthesis of two-dimensional polymer crystals and their structure analysis by X-ray diffraction
Accessing synthetic two-dimensional polymers that are analogous to graphene is synthetically and analytically challenging. Now, single crystals of a simple-to-make monomer have been grown and then photopolymerized to form layered single crystals of covalently bonded two-dimensional polymer. Much like natural graphite, these crystals can be exfoliated to form thin sheets and single layers of the polymer.
- Max J. Kory
- , Michael Wörle
- & A. Dieter Schlüter
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A nanoporous two-dimensional polymer by single-crystal-to-single-crystal photopolymerization
Two-dimensional synthetic polymers can be produced through solid-state topochemical polymerization, but achieving this through a single-crystal-to-single-crystal transformation has not yet been demonstrated. Now, a fluorinated Y-shaped monomer has been preorganized in a lamellar crystal, which goes through two successive single-crystal-to-single-crystal phototransformations to give a 2D polymer; single-crystal X-ray diffraction has been used to elucidate its structure.
- Patrick Kissel
- , Daniel J. Murray
- & Benjamin T. King
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Thesis |
Information-containing macromolecules
Howard Colquhoun and Jean-François Lutz consider the potential of synthetic polymers for storing information at the molecular level.
- Howard Colquhoun
- & Jean-François Lutz
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Colloidal inverse bicontinuous cubic membranes of block copolymers with tunable surface functional groups
Colloidal inverse bicontinuous cubic mesophases have now been formed by self-assembly of amphiphilic dendritic-linear block copolymers in solution. The internal networks of water channels provide a high surface area with tunable functional groups that can serve as anchoring points for macromolecular guests such as proteins and enzymes.
- Yunju La
- , Chiyoung Park
- & Kyoung Taek Kim
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Mechanically triggered heterolytic unzipping of a low-ceiling-temperature polymer
Strong acoustic fields applied to solutions of linear polymers typically result in mid-chain scission, yielding products half the molecular weight of the original. Now it has been shown that poly(o-phthalaldehyde), a polymer with a ceiling temperature below room temperature, undergoes chain scission and subsequent depolymerization to monomers. Introduction of an appropriate initiator to the monomer regenerates poly(o-phthaladehyde) macromolecules.
- Charles E. Diesendruck
- , Gregory I. Peterson
- & Jeffrey S. Moore
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News & Views |
Flex, release and repeat
Force-induced covalent bond changes in mechanophore-linked polymers typically require large, irreversible material deformation, limiting successive activation cycles. Now, repeated force-induced reactions have been achieved by incorporating flex-activated mechanophores into elastomeric networks.
- Nancy R. Sottos
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Switchable enantioseparation based on macromolecular memory of a helical polyacetylene in the solid state
Reversible chirality switching and memory is demonstrated in a helical polyacetylene. Both the helicity of the polymer backbone and the axial chirality of the side chains contribute to the memory effect. When used to produce a chiral stationary phase for a chromatographic enantiomer resolution it was possible to switch the elution order under identical chromatographic conditions.
- Kouhei Shimomura
- , Tomoyuki Ikai
- & Katsuhiro Maeda