~2H-NMR CHARACTERIZATION OF CLAY DISPERSION AND CONFINEMENT EFFECT ON PROBE MOLECULES IN RUBBER/CLAY NANOCOMPOSITE-GELS

~2H-NMR spectroscopy of the probe molecule,deuterated benzene,was applied to characterize organo-clay dispersion and confinement effect on the local motion of benzene in rubber/clay nanocomposite-gels.The observed ~2H line shapes of benzene in intercalated and exfoliated nanocomposites were obviously different,which can be used to estimate clay-dispersion quality.~2H-NMR line shapes also reflect the different influence of intercalated or exfoliated layered-silicates on local motions of benzene,implying that...

Molecular recognition of cyclophanes in water

Molecular recognition in water,the biological solvent,always receives significant research focus in supramolecular chemistry.The mechanisms of molecular recognition in water is key to comprehending biological processes at the molecular level.Over the past five decades,supramolecular chemists have developed a vast array of synthetic receptors with highly diverse structures and recognition properties.Among them,cyclophanes represent an important family of macrocyclic receptors that have been extensively explored.The aromatic moieties in cyclophanes not only facilitate chemical modifications to impart water solubility but also enable forming hydrophobic cavities for guest inclusion in aqueous environments.Pioneered by Koga et al.,who reported the first inclusion complex of cyclophanes in water and solid state,numerous water-soluble cyclophanes,including derivatives of blue box,calixarenes,resorcinarenes,pillararenes,octopusarenes,biphenarenes,coronarenes,and naphthotubes,etc.,have been synthesized and subjected to investigation of the recognition capabilities in aqueous solutions.This review provides an overview of cyclophane receptors designed to bind organic guests in water.We categorize them into two classes based on the modifications made to their hydrophobic cavities:those with“exo-functionalized hydrophobic cavities”and those with“endo-functionalized hydrophobic cavities”.We introduce their distinctive features and discuss strategies to enhance recognition affinity and selectivity.This review aims to inspire the development of novel synthetic receptors with intriguing properties and foster practical applications of cyclophanes.

Azocalixarenes: a scaffold of universal excipients with high efficiency

Excipients are important components of pharmaceutical preparations that affect their quality, safety, and efficacy. Macrocyclic receptors are a family of supramolecular excipients with several advantages, including molecular-level protection, small sizes,fast kinetics of host-guest recognition, and modular construction. With the continuous advances in the medical field, personalized and precision medicine requires the development of excipients with low dosages, integrated modifying effects, universality,and controlled release. To meet these requirements, we have developed a new family of macrocyclic excipients based on calixarenes by integrating their covalent(broad chemical design space) and noncovalent(wide range of substrates) advantages.Accordingly, azocalixarenes(Azo CAs) were designed, showing high binding affinities to a broad spectrum of active pharmaceutical ingredients(APIs), selectivity to interferents, and responsiveness to hypoxic microenvironments. Due to their highly efficient and controllable recognition, Azo CAs serve as low-dose excipients for 30 APIs. Molecular encapsulation by Azo CAs results in the integrated modification of the physicochemical properties of APIs, including solubility, stability, bioavailability,and biocompatibility. Moreover, Azo CAs can be reduced by azoreductases overexpressed in hypoxic microenvironments,leading to the controlled release of APIs. Collectively, Azo CA excipients have broad application prospects for a series of diseases such as enteritis, arthritis, stroke, cancer, bacterial infection and kidney injury, with diverse therapeutic modalities,including chemotherapy, photodynamic therapy, photothermal therapy, immunotherapy, boron neutron capture therapy, radiotherapy, fluorescence imaging, and their combinations.

Synthesis of an Azobenzene-containing Main-chain Crystalline Polymer and Photodeformation Behaviors of Its Supramolecular Hydrogen-bonded Fibers

The synthesis of a new azobenzene(azo)-containing main-chain crystalline polymer with reactive secondary amino groups in its backbone and photodeformation behaviors of its supramolecular hydrogen-bonded fibers are described. This main-chain azo polymer(namely Azo-MP6) was prepared via first the synthesis of a diacrylate-type azo monomer and its subsequent Michael addition copolymerization with trans-1,4-cyclohexanediamine under a mild reaction condition. Azo-MP6 was found to have a linear main-chain chemical structure instead of a branched one, as verified by comparing its ~1H-NMR spectrum with that of the azo polymer prepared via the polymer analogous reaction of AzoMP6 with acetic anhydride. The thermal stability, phase transition behavior, and photoresponsivity of Azo-MP6 were characterized with TGA,DSC, POM, XRD, and UV-Vis spectroscopy. The experimental results revealed that it had good thermal stability, low glass transition temperature,broad crystalline phase temperature range, and highly reversible photoresponsivity. Physically crosslinked supramolecular hydrogen-bonded fibers with good mechanical properties and a high alignment order of azo mesogens were readily fabricated from Azo-MP6 by using the simple melt spinning method, and they could show "reversible" photoinduced bending under the same UV light irradiation and good anti-fatigue properties.

PREPARATION OF SINGLE-HOLE HOLLOW POLYMER NANOSPHERES BY RASPBERRY-LIKE TEMPLATE METHOD

Single-hole hollow polymer nanospheres were fabricated by raspberry-like template method using ＂graft-from＂ strategy through atom transfer radical polymerization （ATRP）. Nanometer-sized silica spheres were covalently attached onto the surfaces of micrometer-sized silica spheres. Crosslinked polymer shells on the nano-sized spheres outside the attached area were formed by ＂graft-from＂ strategy through ATRP. After removal of the silica cores, single-hole hollow crosslinked polymer nanospheres were obtained. In this strategy, most of ATRP monomers may be used and thus many functional groups can be easily incorporated into the single-hole hollow crosslinked polymer nanospheres.

Cisplatin-loaded Polymer/Magnetite Composite Nanoparticles as Multifunctional Therapeutic Nanomedicine

Multifunctional nanocarriers with multilayer core-shell architecture were prepared by coating superparamagnetic Fe3O4 nanoparticles with diblock copolymer folate-poly（ethylene glycol）-b-poly（glycerol monomethacrylate） （FA-PEG-b- PGMA）, and triblock copolymer methoxy poly（ethylene glycol）-b-poly（2-（dimethylamino） ethyl methacrylate）-b- poly（glycerol monomethacrylate） （MPEG-b-PDMA-b-PGMA）. The PGMA segment was attached to the surfaces of Fe304 nanoparticles, and the outer PEG shell imparted biocompatibility. In addition, folate was conjugated onto the surfaces of the nanocarriers. Cisplatin was then loaded into the nanocarrier by coordination between the Pt atom in cisplatin and the amine groups in the inner shell of the multilayer architecture. The loaded cisplatin showed pH-responsive release： slower release at pH 7.4 （i.e. mimicking the blood environment） and faster release at more acidic pH （i.e. mimicking endosome/lysosome conditions）. All of the cisplatin-loaded nanoparticles showed concentration-dependent cytotoxicity in HeLa cells. However, the folate-conjugated cisplatin-loaded carriers exhibited higher cytotoxicity in HeLa cells than non-folate conjugated cisplatin-loaded carriers.

Inhibition of insulin fibrillation by amphiphilic sulfonatocalixarene

Insulin fibrillation poses a variety of problems in biomedical and biotechnological applications of insulin.Inhibiting insulin fibrillation is highly on demand to address those problems.We herein demonstrate the capability of amphiphilic sulfonatocalixarene to inhibit insulin fibrillation.The amphiphilic assembly of p-sulfonatocalix[4]arene tetra dodecyl ether exhibits much better efficiency on inhibiting insulin fibrillation,with respect to p-sulfonatocalix[4]arene and sodium dodecyl benzenesulphonate.The pronounced inhibition effect results from both the preorganized scaffold of calixarene and the amphiphilic assembly.

Functional Poly(ionic liquid)Porous Membranes:From Fabrications to Advanced Applications

Polyelectrolyte porous membranes(PPMs)belong to the most interesting classes of materials,because the synergy of tunable pore sizes and charge nature of polyelectrolyte endow them with wide-ranging practical applications.However,owing to the water solu-bility and ionic nature of the polyelectrolytes,traditional polyelectrolytes are difficult to use in scalable preparation of high-quality PPMs through the well-developed industrial methods.Poly(ionic liquid)s(PIL)are a subclass of functional polyelectrolytes bearing ionic liquid groups in their repeating unites,inheriting the advantages of ionic liquids(ILs)and macromolecular architecture features.In recent years,along with rapid development of PIL materials chemistry,considerable and significant developments involving the novel preparation methods,and structure-property-function relationships of PPMs have been made.In this review,we highlight the latest discovery and proceedings of PPMs,particularly the advancements in how to tailor structures and properties of PPMs by ra-tional structure design of PILs.The formation mechanisms of various PPMs were also discussed in detail from the viewpoint of PILs molecular structures.A future perspective of the challenges and promising potential of PPMs is cast on the basis of these achieve-ments.We expect that these analyses and deductions will be useful for the design of useful PPMs and serve as a source of inspira-tion for the design of future multifunctional PPMs.

Host-Guest Sensor Array for Discriminating G-Quadruplexes

Rapid classification of the secondary structures of nucleic acids,such as G-quadruplexes(G4s)is desirable but very challenging due to the high similarity among different folding.Chen et al.constructed a host-guest sensor array to differentiate the topology of unmodified G4s for the first time.

Advanced Heteroatom-Doped Porous Carbon Membranes Assisted by Poly(ionic liquid)Design and Engineering

CONSPECTUS:Heteroatom-doped porous carbon membranes(HPCMMs)with a tailor-made pore architecture,chemical composition,atomic structural order,and surface state represent an exciting family of porous carbon materials for diverse potential applications in catalysis,water treatment,biofiltration,energy conversion/storage,and so forth.Conventional porous carbon membranes possess intrinsic structural integrity,interconnectivity,and chemical purity across the atomic-to-macro world and have been popularly incorporated into devices as separators or chemically inert conductive supports,circumventing otherwise the inevitable complicated processing and structure weakness of their fine powderous counterpart.Motivated by the distinguished heteroatom-doping effect that revolutionizes the chemical and physical nature of carbon materials,the HPCMM research surges very recently,and focuses not only on the eminent conductive supports or separators but also on electro(co)catalysts in energy devices.Synergy of the porous nature,incorporation of heteroatoms,and the membrane state creates a vivid profile pattern and new task-specific usage.It is also noteworthy that the inherent structural merits of HPCMMs plus a high electron conductivity imbue them as a reliable binder-free model electrode to derive the intrinsic structure−property relationship of porous carbons in electrochemical environments,excluding the complex and adverse factors in association with polymer binders in carbon powder-based electrodes.HPCMMs are of both intense academic interest and practical value because of their well-defined properties endowed by controllable structure and porosity at both atomic and macroscopic scales in a membrane form.The sole aim of this article is to bring this group of porous carbon materials to the forefront so their comprehensive properties and functions can be better understood to serve the carbon community to address pressing materials challenges in our society.In this Account,we highlight the latest discovery and proceedings of HPCMMs,particularly the advancements in how to tailor structures and properties of HPCMMs by rational structure design of porous polymer membranes as sacrificial template built up especially from heteroatom-rich poly(ionic liquid)s(PILs).We will also stress the carbonization craft and the state-of-the-art electrochemical applications for HPCMMs.Key factors and thoughts in heteroatom doping and porous systems in HPCMMs are discussed.A future perspective of the challenges and promising potential of HPCMMs is cast on the basis of these achievements.