Sustainable Composite Materials Based on Carnauba Wax and Montmorillonite Nanoclay for Energy Storage.

Sustainable composite materials, including carnauba wax, can store energy in the form of latent heat, and containing the wax may allow form-stable melting and crystallization cycles to be performed. Here, it is shown that carnauba wax in the molten state and the abundant nanoclay montmorillonite form stable composites with mass ratios of 50-70% (/). Transmission electron microscopy analysis reveals the inhomogeneous distribution of the nanoclay in the wax matrix.

Coupled reaction equilibria enable the light-driven formation of metal-functionalized molecular vanadium oxides.

The introduction of metal sites into molecular metal oxides, so-called polyoxometalates, is key for tuning their structure and reactivity. The complex mechanisms which govern metal-functionalization of polyoxometalates are still poorly understood. Here, we report a coupled set of light-dependent and light-independent reaction equilibria controlling the mono- and di-metal-functionalization of a prototype molecular vanadium oxide cluster.

Lithium confinement and dynamics in hexagonal and monoclinic tungsten oxide nanocrystals: a Li solid state NMR study.

Mixed-valence tungsten bronzes AWO (A = alkali metal, NH, .) are a series of compounds with adaptive structural and compositional features that make them a hot research topic in thermoelectrics, electrochromics, catalysis or energy applications in battery electrodes. The mixed hexagonal lithium ammonium bronze Li(NH)WO is a new member of this structural family whose properties are compared to those of the pure hexagonal tungsten bronze (NH)WO.

Styryl dyes with N-Methylpiperazine and N-Phenylpiperazine Functionality: AT-DNA and G-quadruplex binding ligands and theranostic agents.

New monomethine, unsymmetrical styryl dyes consisting of benzothiazole and N-methylpiperazine or N-phenylpiperazine scaffolds were synthesized, and their binding affinities for different ds-polynucleotides and G-quadruplex were studied. Substitution of piperazine unit with methyl or phenyl group strongly influenced their binding modes, binding affinities, spectroscopic responses and antiproliferative activities. Compounds with N-methylpiperazine substituents showed a significant preference for AT-DNA polynucleotides and demonstrated AT-minor groove binding, which manifested in strong fluorescence increase, significant double helix stabilization, and positive induced circular dichroism spectra.

Generalized synthesis of NaCrO particles for high-rate sodium ion batteries prepared by microfluidic synthesis in segmented flow.

NaCrO particles for high-rate sodium ion batteries were prepared on a multigram scale in segmented flow from chromium nitrate and sodium nitrate using a segregated flow water-in-oil emulsion drying process. Microfluidic processing is an environmentally friendly and rapid synthetic method, which can produce large-scale industrial implementation for the production of materials with superior properties. The reaction time for NaCrO particles was reduced by almost one order of magnitude compared to a normal flask synthesis and by several orders of magntitude compared to a conventional solid-state reaction.

Cell Adhesion on UV-Crosslinked Polyurethane Gels with Adjustable Mechanical Strength and Thermoresponsiveness.

Temperature-responsive polyurethane (PU) hydrogels represent a versatile material platform for modern tissue engineering and biomedical applications. However, besides intrinsic advantages such as high mechanical strength and a hydrolysable backbone composition, plain PU materials are generally lacking bio-adhesive properties. To overcome this shortcoming, the authors focus on the synthesis of thermoresponsive PU hydrogels with variable mechanical and cell adhesive properties obtained from linear precursor PUs based on poly(ethylene glycol)s (pEG) with different molar masses, isophorone diisocyanate, and a dimerizable dimethylmaleimide (DMMI)-diol.

Magneli-type tungsten oxide nanorods as catalysts for the selective oxidation of organic sulfides.

Selective oxidation of thioethers is an important reaction to obtain sulfoxides as synthetic intermediates for applications in the chemical industry, medicinal chemistry and biology or the destruction of warfare agents. The reduced Magneli-type tungsten oxide WO possesses a unique oxidase-like activity which facilitates the oxidation of thioethers to the corresponding sulfoxides. More than 90% of the model system methylphenylsulfide could be converted to the sulfoxide with a selectivity of 98% at room temperature within 30 minutes, whereas oxidation to the corresponding sulfone was on a time scale of days.

Polycationic Monomeric and Homodimeric Asymmetric Monomethine Cyanine Dyes with Hydroxypropyl Functionality-Strong Affinity Nucleic Acids Binders.

New analogs of the commercial asymmetric monomethine cyanine dyes thiazole orange (TO) and thiazole orange homodimer (TOTO) with hydroxypropyl functionality were synthesized and their properties in the presence of different nucleic acids were studied. The novel compounds showed strong, micromolar and submicromolar affinities to all examined DNA ds-polynucleotides and poly rA-poly rU. The compounds studied showed selectivity towards GC-DNA base pairs over AT-DNA, which included both binding affinity and a strong fluorescence response.

Rational Design of Thermoresponsive Microgel Templates with Polydopamine Surface Coating for Microtissue Applications.

Functional microgels provide a versatile basis for synthetic in vitro platforms as alternatives to animal experiments. The tuning of the physical, chemical, and biological properties of synthetic microgels can be achieved by blending suitable polymers and formulating them such to reflect the heterogenous and complex nature of biological tissues. Based on this premise, this paper introduces the development of volume-switchable core-shell microgels as 3D templates to enable cell growth for microtissue applications, using a systematic approach to tune the microgel properties based on a deep conceptual and practical understanding.

High-speed solid state fluorination of NbO yields NbOF and NbOF with photocatalytic activity for oxygen evolution from water.

Solid state reactions are slow because the diffusion of atoms or ions through the reactant, intermediate and crystalline product phases is the rate-limiting step. This requires days or even weeks of high temperature treatment, and consumption of large amounts of energy. We employed spark-plasma sintering, an engineering technique that is used for high-speed consolidation of powders with a pulsed electric current passing through the sample to carry out the fluorination of niobium oxide in minute intervals.

Gram-scale selective synthesis of WO nanorods and (NH)WO ammonium tungsten bronzes with tunable plasmonic properties.

Localized surface plasmon resonance properties in unconventional materials like metal oxides or chalcogenide semiconductors have been studied for use in signal detection and analysis in biomedicine and photocatalysis. We devised a selective synthesis of the tungsten oxides WO and (NH)WO with tunable plasmonic properties. We selectively synthesized WO nanorods with different aspect ratios and hexagonal tungsten bronzes (NH)WO as truncated nanocubes starting from ammonium metatungstate (NH)HWO·xHO.

A Generalized Method for High-Speed Fluorination of Metal Oxides by Spark Plasma Sintering Yields Ta O F and TaO F with High Photocatalytic Activity for Oxygen Evolution from Water.

A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta O F and TaO F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination.

Synthesis of Au, Ag, and Au-Ag Bimetallic Nanoparticles Using Extract and Their Catalytic Activity for the Reduction of 4-Nitrophenol.

Plant extract of (L.) was used as both reducing agent and stabilizing ligand for the rapid and green synthesis of gold (Au), silver (Ag), and gold-silver (Au-Ag) bimetallic (phase segregated/alloy) nanoparticles (NPs). These nanoparticles with different morphologies were prepared in two hours by stirring corresponding metal precursors in the aqueous solution of the plant extracts at ambient temperature.

Mixed Ligand Shell Formation upon Catechol Ligand Adsorption on Hydrophobic TiO Nanoparticles.

Modifying the surfaces of metal oxide nanoparticles (NPs) with monolayers of ligands provides a simple and direct method to generate multifunctional coatings by altering their surface properties. This works best if the composition of the monolayers can be controlled. Mussel-inspired, noninnocent catecholates stand out from other ligands like carboxylates and amines because they are redox-active and allow for highly efficient surface binding and enhanced electron transfer to the surface.

Polymer-Functionalised Nanograins of Mg-Doped Amorphous Calcium Carbonate via a Flow-Chemistry Approach.

Calcareous biominerals typically feature a hybrid nanogranular structure consisting of calcium carbonate nanograins coated with organic matrices. This nanogranular organisation has a beneficial effect on the functionality of these bioceramics. In this feasibility study, we successfully employed a flow-chemistry approach to precipitate Mg-doped amorphous calcium carbonate particles functionalized by negatively charged polyelectrolytes-either polyacrylates (PAA) or polystyrene sulfonate (PSS).

Trapping Amorphous Intermediates of Carbonates - A Combined Total Scattering and NMR Study.

Crystallization via metastable phases plays an important role in chemical manufacturing, biomineralization, and protein crystallization, but the kinetic pathways leading from metastable phases to the stable crystalline modifications are not well understood. In particular, the fast crystallization of amorphous intermediates makes a detailed characterization challenging. To circumvent this problem, we devised a system that allows trapping and stabilizing the amorphous intermediates of representative carbonates (calcium, strontium, barium, manganese, and cadmium).

Hydrogen Bonding in Amorphous Alkaline Earth Carbonates.

Amorphous intermediates play a crucial role during the crystallization of alkaline earth carbonates. We synthesized amorphous carbonates of magnesium, calcium, strontium, and barium from methanolic solution. The local environment of water and the strength of hydrogen bonding in these hydrated modifications were probed with Fourier transform IR spectroscopy, H NMR spectroscopy, and heteronuclear correlation experiments.

Calcium Sulfate Nanoparticles with Unusual Dispersibility in Organic Solvents for Transparent Film Processing.

Calcium sulfate is one of the most important construction materials. Today it is employed as high-performance compound in medical applications and cement mixtures. We report a synthesis for calcium sulfate nanoparticles with outstanding dispersibility properties in organic solvents without further functionalization.

Al NMR Study of the pH Dependent Hydrolysis Products of Al₂(SO₄)₃ in Different Physiological Media.

Soluble inorganic aluminium compounds like aluminium sulfate or aluminium chloride have been challenged by the European Chemical Agency to induce germ cell mutagenicity. Before conducting mutagenicity tests, the hydrolysis products in water and in physiological solutions should be determined as a function of the concentration and pH. We used different Al NMR spectroscopic techniques (heteronuclear Overhauser effect spectroscopy (HOESY), exchange spectroscopy (EXSY), diffusion ordered (DOSY)) in this work to gain the information to study the aluminium species in solutions with Al₂(SO₄)₃ concentrations of 50.

Monitoring Thiol-Ligand Exchange on Au Nanoparticle Surfaces.

Surface functionalization of nanoparticles (NPs) plays a crucial role in particle solubility and reactivity. It is vital for particle nucleation and growth as well as for catalysis. This raises the quest for functionalization efficiency and new approaches to probe the degree of surface coverage.

Glycine-functionalized copper(ii) hydroxide nanoparticles with high intrinsic superoxide dismutase activity.

Superoxide dismutases (SOD) are a group of enzymes that catalyze the dismutation of superoxide (O) radicals into molecular oxygen (O) and HO as a first line of defense against oxidative stress. Here, we show that glycine-functionalized copper(ii) hydroxide nanoparticles (Gly-Cu(OH) NPs) are functional SOD mimics, whereas bulk Cu(OH) is insoluble in water and catalytically inactive. In contrast, Gly-Cu(OH) NPs form water-dispersible mesocrystals with a SOD-like activity that is larger than that of their natural CuZn enzyme counterpart.

Nonclassical crystallization in vivo et in vitro (I): Process-structure-property relationships of nanogranular biominerals.

A distinct nanogranular fine structure is shared by a wealth of biominerals from several species, classes and taxa. This nanoscopic organization affects the properties and behavior of the biogenic ceramic material and confers on them attributes that are essential to their function. We present a set of structure-relationship properties that are rooted in the nanogranular organization and we propose that they rest on a common pathway of formation, a colloid-driven and hence nonclassical mode of crystallization.

Combining Neopentyllithium with Potassium tert-Butoxide: Formation of an Alkane-Soluble Lochmann-Schlosser Superbase.

Mixtures of alkyllithium and heavier alkali-metal alkoxides are often used to form alkyl compounds of heavier alkali metals, but these mixtures are also known for their high reactivity in deprotonative metalation reactions. These organometallic mixtures are often called LiC-KOR superbases, but despite many efforts their constitution remains unknown. Herein we present mixed alkali-metal alkyl/alkoxy compounds produced by reaction of neopentyllithium with potassium tert-butoxide.

Anhydrous Amorphous Calcium Oxalate Nanoparticles from Ionic Liquids: Stable Crystallization Intermediates in the Formation of Whewellite.

The mechanisms by which amorphous intermediates transform into crystalline materials are not well understood. To test the viability and the limits of the classical crystallization, new model systems for crystallization are needed. With a view to elucidating the formation of an amorphous precursor and its subsequent crystallization, the crystallization of calcium oxalate, a biomineral widely occurring in plants, is investigated.

(1-Adamantyl)methyl glycidyl ether: a versatile building block for living polymerization.

(1-Adamantyl)methyl glycidyl ether (AdaGE) is introduced as a versatile monomer for oxyanionic polymerization, enabling controlled incorporation of adamantyl moieties in aliphatic polyethers. Via copolymerization with ethoxyethyl glycidyl ether (EEGE) and subsequent cleavage of the acetal protection groups of EEGE, hydrophilic linear polyglycerols with an adjustable amount of pendant adamantyl moieties are obtained. The adamantyl unit permits control over thermal properties and solubility profile of these polymers (LCST).