Showing papers in "Science China-chemistry in 2012"
TL;DR: The work suggests that GO does actual toxicity to organisms posing potential environmental risks and the result is also shedding light on the geometrical structure-dependent toxicity of graphitic nanomaterials.
Abstract: Graphene possesses unique physical and chemical properties, which have inspired a wide range of potential biomedical applications. However, little is known about the adverse effects of graphene on the human body and ecological environment. The purpose of our work is to make assessment on the toxicity of graphene oxide (GO) against human cell line (human bone marrow neuroblastoma cell line and human epithelial carcinoma cell line) and zebrafish (Danio rerio) by comparing the toxic effects of GO with its sister, multi-walled carbon nanotubes (MWNTs). The results show that GO has a moderate toxicity to organisms since it can induce minor (about 20%) cell growth inhibition and slight hatching delay of zebrafish embryos at a dosage of 50 mg/L, but did not result in significant increase of apoptosis in embryo, while MWNTs exhibit acute toxicity leading to a strong inhibition of cell proliferation and serious morphological defects in developing embryos even at relatively low concentration of 25 mg/L. The distinctive toxicity of GO and MWNTs should be ascribed to the different models of interaction between nanomaterials and organisms, which arises from the different geometric structures of nanomaterials. Collectively, our work suggests that GO does actual toxicity to organisms posing potential environmental risks and the result is also shedding light on the geometrical structure-dependent toxicity of graphitic nanomaterials.
149 citations
TL;DR: In this article, a mesoporous silica SBA-SBA-15 was fabricated through post-grafting method and its adsorptivity for U(VI) from aqueous solution was investigated using batch sorption technique under different experimental conditions.
Abstract: Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino bifunctionalized mesoporous silica SBA-15 (PA-SBA-15) as U(VI) sorbent was fabricated through post-grafting method. The obtained mesoporous silica was characterized by SEM, XRD, NMR and nitrogen sorption/desorption experiments, which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area. The adsorptivity of PA-SBA-15 for U(VI) from aqueous solution was investigated using batch sorption technique under different experimental conditions. The preliminary results show that the U(VI) sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h, and the U(VI) uptake is as large as 373 mg/g at pH 5.5 under 95 °C. The sorption isotherm has been successfully modeled by the Langmuir isotherm, suggesting a monolayer homogeneous sorption of U(VI) in PA-SBA-15. The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution. The thermodynamics research shows that the sorption is a feasible and endothermic process. Based on these results, PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U(VI) ions from waste water and enrichment of U(VI) from a solution at a very low level.
72 citations
TL;DR: In this paper, the most suitable ionic liquids for the extraction of aromatic hydrocarbons from a mixture of aromatic and aliphatic polycarbonates are [bmim]C(CN)3, [3-mebupy]N(CN), [3meb upy]C[CN]N[3]-2, [ 3-meupy]-C[3-MEBupy[C[N]-N[N]2] and [Mebupyrr]B[B]-B[CN]-4.
Abstract: Ionic liquids can replace conventional solvents in aromatic/aliphatic extractions, if they have higher aromatic distribution coefficients and higher or similar aromatic/aliphatic selectivities. Also physical properties, such as density and viscosity, must be taken into account if a solvent is applied in an industrial extraction process. Cyano-containing ionic liquids have a lower density than the benchmark solvent sulfolane and a higher viscosity. Sulfolane is from a hydrodynamic point of view a better solvent than ionic liquids for the aromatic/aliphatic extraction. The most suitable ionic liquids for the extraction of aromatic hydrocarbons from a mixture of aromatic and aliphatic hydrocarbons are [bmim]C(CN)3, [3-mebupy]N(CN)2, [3-mebupy]C(CN)3, [3-mebupy]B(CN)4 and [mebupyrr]B(CN)4. They have factors of 1.2–2.3 higher mass-based distribution coefficients than sulfolane and a similar or higher, up to a factor of 1.9 higher, aromatic/aliphatic selectivity than sulfolane. The IL [3-mebupy]N(CN)2 is a better extractant for the separation of toluene from a mixture of toluene/n-heptane in a pilot plant Rotating Disc Contactor (RDC) than sulfolane.
72 citations
TL;DR: A facile method for the synthesis of pillar[6]arenes was developed in this paper, where a series of pillars were prepared with FeCl3 as catalyst and chloroform as solvent at room temperature in moderate yields (30% to 40%).
Abstract: A facile method for the synthesis of pillar[6]arenes was developed. A series of pillar[6]arenes were prepared with FeCl3 as catalyst and chloroform as solvent at room temperature in moderate yields (30%–40%). Their host-guest properties with n-cetyltrimethyl ammonium bromide were investigated by 1 HNMR. The results showed that high selectivity in the host-guest relationship became apparent between pillar[6]arenes and pillar[5]arenes based on the different size of the inner cavity.
68 citations
TL;DR: In this paper, a series of Mo-doped ZnO photocatalysts with different Modopant concentrations have been prepared by a grinding-calcination method.
Abstract: A series of Mo-doped ZnO photocatalysts with different Mo-dopant concentrations have been prepared by a grinding-calcination method. The structure of these photocatalysts was characterized by a variety of methods, including N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, photoluminescence (PL) emission spectroscopy, and UV-vis diffuse reflectance spectroscopy (DRS). It was found that Mo6+ could enter into the crystal lattice of ZnO due to the radius of Mo6+ (0.065 nm) being smaller than that of Zn2+ (0.083 nm). XRD results indicated that Mo6+ suppressed the growth of ZnO crystals. The FT-IR spectroscopy results showed that the ZnO with 2 wt.% Mo-doping has a higher level of surface hydroxyl groups than pure ZnO. PL spectroscopy indicated that ZnO with 2 wt.% Mo-doping also exhibited the largest reduction in the intensity of the emission peak at 390 nm caused by the recombination of photogenerated hole-electron pairs. The activities of the Mo-doped ZnO photocatalysts were investigated in the photocatalytic degradation of acid orange II under UV light (λ = 365 nm) irradiation. It was found that ZnO with 2 wt.% Mo-doping showed much higher photocatalytic activity and stability than pure ZnO. The high photocatalytic performance of the Mo-doped ZnO can be attributed to a great improvement in the surface properties of ZnO, higher crystallinity and lower recombination rate of photogenerated hole-electron (e−/h+) pairs. Moreover, the undoped Mo species may exist in the form of MoO3 and form MoO3/ZnO heterojunctions which further favors the separation of e−/h+ pairs.
67 citations
TL;DR: In this article, a review of the achievements of the groups worldwide, and particularly the work carried out in our own laboratory towards strength recovery for structural applications, is presented. And innovative routes that correlate materials chemistry to full capacity restoration are discussed for further development from bioinspired toward biomimetic repair.
Abstract: Self-healing polymers represent a class of materials with built-in capability of rehabilitating damages. The topic has attracted increasingly more attention in the past few years. The on-going research activities clearly indicate that self-healing polymeric materials turn out to be a typical multi-disciplinary area concerning polymer chemistry, organic synthesis, polymer physics, theoretical and experimental mechanics, processing, composites manufacturing, interfacial engineering, etc. The present article briefly reviews the achievements of the groups worldwide, and particularly the work carried out in our own laboratory towards strength recovery for structural applications. To ensure sufficient coverage, thermoplastics and thermosetting polymers, extrinsic and intrinsic self-healing, autonomic and non-autonomic healing approaches are included. Innovative routes that correlate materials chemistry to full capacity restoration are discussed for further development from bioinspired toward biomimetic repair.
62 citations
TL;DR: In this paper, a novel strategy for preparing redox-active electrolyte through introducing a redoxmediator (p-phenylenediamine, PPD) into KOH electrolyte for the application of ball-milled MnO2-based supercapacitors was reported.
Abstract: This paper reports a novel strategy for preparing redox-active electrolyte through introducing a redox-mediator (p-phenylenediamine, PPD) into KOH electrolyte for the application of ball-milled MnO2-based supercapacitors. The morphology and compositions of ball-milled MnO2 were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical properties of the supercapacitor were evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The introduction of p-phenylenediamine significantly improves the performance of the supercapacitor. The electrode specific capacitance of the supercapacitor is 325.24 F g−1, increased by 6.25 folds compared with that of the unmodified system (44.87 F g−1) at the same current density, and the energy density has nearly a 10-fold increase, reaching 10.12 Wh Kg−1. In addition, the supercapacitor exhibits good cycle-life stability.
62 citations
TL;DR: In this article, a review summarizes the preparation methods of support ionic liquids (SILs) and their applications in rare metals separation, including the recovery of high value metal ions and the removal of heavy metal ions from wastewater.
Abstract: This review summarizes the preparation methods of support ionic liquids (SILs) and their applications in rare metals separation. The rare metals separation includes the recovery of high value metal ions and the removal of heavy metal ions from wastewater. SILs can be used as a kind of highly efficient multifunctional separation materials. The preparation methods of SILs include chemical immobilization technique in which ILs moieties are supported on solid supports via covalent bonds and physical immobilization techniques in which ILs are immobilized on solid supports via physical method such as simple impregnation, sol-gel method. According to the difference of solid supports, this review summarizes the application of polymer supported ionic liquids (P-SILs), silica based material supported ionic liquids (SM-SILs) and membrane supported ionic liquids (M-SILs) in rare metals separation. P-SILs and SM-SILs prepared by chemical method with N-methylimidazolium group can be used as highly efficient anion exchangers with high thermal stability and good chemical stability for adsorption of Cr(VI), Re(VII), Ce(IV). P-SILs prepared via simple impregnation afforded IL functionalized solvent impregnated resins (SIRs) which showed high separation efficiency and selectivity in the separation of rare earths(III) (REs(III)). SM-SILs prepared via sol-gel method with IL doped in the support as porogens or extractant show high removal efficiencies and excellent stability for the separation of RE(III), Cr(III) and Cr(VI). M-SILs with IL as plasticizer or carrier show improved stability, high permeability coefficient and good selectivity for Cr(VI) transport. Different supports and different supporting methods were sufficiently compared. Based on the different practical application, different forms of SILs can be prepared for separation of rare metals with high separation efficiency and selectivity.
59 citations
TL;DR: In this paper, the photoelectric conversion properties of organic sensitizers based on donor-π-acceptor dyes have been investigated in the context of dye-sensitized solar cells.
Abstract: Functional organic dyes have promising prospect in dye-sensitized solar cells as a crucial element, of which sensitizers based on donor-π-acceptor are the most important dyes. On the basis of the structures of the aromatic amine donors such as triphenylamine and indoline, this paper reviews the photoelectric conversion properties of organic sensitizers since 2008, and highlights research work in our laboratory in this area.
58 citations
TL;DR: The Vogel-Tammann-Fulcher (VTF) equations can be used to fit the viscosity and conductivity of all the neat ionic liquids and the binary mixtures.
Abstract: The density, viscosity and conductivity of ionic liquids (ILs), 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF4]), 1-octyl-3-methylimidazolium chloride ([omim][Cl]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim] BF4]), 1-hexyl- 3-methylimidazolium chloride ([hmim][Cl]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF6]), and the [omim][BF4] + [omim][Cl], [hmim][BF4] + [hmim][Cl], and [hmim][PF6] + [hmim][Cl] binary mixtures were studied at different temperatures. It was demonstrated that the densities of both the neat ILs and their mixtures varied linearly with temperature. The density sensitivity of a binary mixture is between those of the two components. The excess molar volumes ( V E) of [hmim][BF4] + [hmim][Cl] and [hmim][PF6] + [hmim][Cl] mixtures are positive in the whole composition range. For [omim][BF4] + [omim][Cl], the V E is also positive in the [omim][Cl]-rich region, but is negative in the [omim][BF4]-rich region. The viscosity or conductivity of a mixture is in the intermediate of those of the two neat ILs. For all the neat ILs and the binary mixtures studied, the order of conductivity is opposite to that of the viscosity. The Vogel-Tammann-Fulcher (VTF) equations can be used to fit the viscosity and conductivity of all the neat ILs and the binary mixtures. The neat ILs and their mixtures obey the Fractional Walden Rule very well, and the values of the Walden slopes are all smaller than unit, indicating obvious ion associations in the neat ILs and the binary mixtures.
57 citations
TL;DR: In this article, the effects of pH, contact time and natural organic ligands on radionuclide Eu(III) adsorption and mechanism on titanate nanotubes (TNTs) are studied by a combination of batch and extended X-ray absorption fine structure (EXAFS) techniques.
Abstract: The effects of pH, contact time and natural organic ligands on radionuclide Eu(III) adsorption and mechanism on titanate nanotubes (TNTs) are studied by a combination of batch and extended X-ray absorption fine structure (EXAFS) techniques. Macroscopic measurements show that the adsorption is ionic strength dependent at pH 6.0. The presence of humic acid (HA) / fulvic acid (FA) increases Eu(III) adsorption on TNTs at low pH, but reduces Eu(III) adsorption at high pH. The results of EXAFS analysis indicate that Eu(III) adsorption on TNTs is dominated by outer-sphere surface complexation at pH 6.0. At pH < 6.0, Eu(III) consists of ∼ 9 O atoms at R
Eu-O ≈ 2.40 A in the first coordination sphere, and a decrease in NEu-O with increasing pH indicates the introduction of more asymmetry in the first sphere of adsorbed Eu(III). At long contact time or high pH values, the Eu(III) consists of ∼2 Eu at R
Eu-Eu ≈ 3.60 A and ∼ 1 Ti at R
Eu-Ti ≈ 4.40 A, indicating the formation of inner-sphere surface complexation, surface precipitation or surface polymers. Surface adsorbed HA/FA on TNTs modifies the species of adsorbed Eu(III) as well as the local atomic structures of adsorbed Eu(III) on HA/FA-TNT hybrids. Adsorbed Eu(III) on HA/FA-TNT hybrids forms both ligand-bridging ternary surface complexes (Eu-HA/FA-TNTs) as well as surface complexes in which Eu(III) remains directly bound to TNT surface hydroxyl groups (i.e., binary Eu-TNTs or Eu-bridging ternary surface complexes (HA/FA-Eu-TNTs)). The findings in this work are important to describe Eu(III) interaction with nanomaterials at molecular level and will help to improve the understanding of Eu(III) physicochemical behavior in the natural environment.
TL;DR: In this paper, the authors highlight several recent significant results that have made impacts toward the field of flexible and stretchable electronics, sensors and power sources, and highlight several important developments in this area.
Abstract: There has been ongoing keen interest to mold electronic devices into desired shapes and be laid on desired configurable surfaces. In specific, the ability to design materials that can bend, twist, compress and stretch repeatedly, while still able to maintain its full capability as conductors or electrodes, has led to numerous efforts to develop flexible and stretchable (bio)devices that are both technologically challenging and environmentally friendly (e.g. biodegradable). In this review, we highlight several recent significant results that have made impacts toward the field of flexible and stretchable electronics, sensors and power sources.
TL;DR: In this article, the enthalpies of pyridinium-based ionic liquids with bis(trifluoromethylsulfonyl)imide anion [C n Py][NTf2] (n = 2, 3, 4, 5, and 6) have been determined with the quartz crystal microbalance technique combined with the Langmuir evaporation.
Abstract: The enthalpies of vaporization for the series of pyridinium-based ionic liquids with bis(trifluoromethylsulfonyl)imide anion [C n Py][NTf2] ( n = 2, 3, 4, 5, and 6) have been determined with the quartz crystal microbalance technique combined with the Langmuir evaporation. The linear dependence of vaporization enthalpies on the chain length has been revealed. New approach based on volumetric, surface tension, and speed of sound measurements has been developed for estimation of heat capacity differences between gas and liquid phase, which were required for adjustment of measured vaporization enthalpies to the reference temperature 298 K.
TL;DR: In this paper, a non-classical crystallization mechanism is discussed for their possibilities in morphology control of hierarchically-structured materials, in which the self-organization of preformed building blocks as nanosized subunits, whose oriented attachment leads to mesocrystals with favorable morphology and texture.
Abstract: Hierarchical structures, in which structure is generated and controlled simultaneously at different size scales, have attracted increasing attention due to their potentials in both theoretical research and practical applications. In this review, a “non-classical crystallization” mechanism is discussed for their possibilities in morphology control of hierarchically-structured materials. Differently, this crystallization route is not based on the attaching and detaching of monomers as happened in the classical case, but through the self-organization of preformed building blocks as nanosized subunits, whose oriented attachment leads to mesocrystals with favorable morphology and texture. Representative materials including both inorganic and organic crystals are reported with possible mechanisms proposed. Synthetic protocols based on this mechanism provide unique inspirations for materials design and could be applied to morphological and structural control of new materials with optimized functions.
TL;DR: In this paper, the sorption behavior and microscopic sequestration mechanisms of radionuclide 63Ni(II) on mordenite as a function of aging time, ionic strength, initial 63Ni (II) concentrations, solid content and coexistent electrolyte ions were investigated by the combination of batch and EXAFS techniques.
Abstract: The sorption behavior and microscopic sequestration mechanisms of radionuclide 63Ni(II) on mordenite as a function of aging time, ionic strength, initial 63Ni(II) concentrations, solid content and coexistent electrolyte ions were investigated by the combination of batch and EXAFS techniques. Macroscopic experiment results show that the sorption of 63Ni(II) is dependent on ionic strength at pH 7. The sorption percentage of 63Ni(II) on mordenite increases with increasing solid content, while the sorption capacity decreases as solid content increases. The presence of different electrolyte ions can enhance or inhibit the sorption of Ni(II) on mordenite in various degrees. EXAFS analysis results of the samples under three different ionic strengths suggest that the retained 63Ni(II) in these samples exists in an octahedral environment with six water ligands. In the initial period of rapid uptake, the sorption of 63Ni(II) is dominated by the formation of inner-sphere surface complexes. As aging time increases, 63Ni(II) sequestration behavior tends to be mainly controlled by the formation of Ni phyllosilicate co-precipitates and/or Ni(OH)2(s) precipitates. Results for the second shell fit of the sample prepared at an initial 63Ni(II) concentration of 100 mg/L indicate the possible formation of Ni polynuclear surface complexes. Both the macroscopic sorption data and the molecular level evidence of 63Ni(II) surface speciation at the mordenite/water interfaces should be factored into better predictions of the mobility and bioavailability of 63Ni(II) in environment mediums.
TL;DR: In this paper, the same crude product contains polydisperse nanoclusters and was then used as the common starting material for controlled growth of Au25 (SR)18 and Au38(SR)24, respectively.
Abstract: We report the controlled growth of Au25(SR)18 and Au38(SR)24 (where R = CH2CH2Ph) nanoclusters of molecular purity via size-focusing from the same crude product that contains a distribution of nanoclusters. In this method, gold salt was first mixed with tetraoctylammonium bromide (TOAB), and then reacted with excess thiol to form Au(I)-SR polymers in THF (as opposed to toluene in previous work), followed by NaBH4 reduction. The resultant crude product contains polydisperse nanoclusters and was then used as the common starting material for controlled growth of Au25(SR)18 and Au38(SR)24, respectively. In Route I, Au25(SR)18 nanoclusters of molecular purify were produced from the crude product after 6 h aging at room temperature. In Route II, the crude product was isolated and further subjected to thermal thiol etching in a toluene solution containing excess thiol, and one obtained pure Au38(SR)24 nanoclusters, instead of Au25(SR)18. This work not only provides a robust and simple method to prepare both Au25(SR)18 and Au38(SR)24 nanoclusters, but also reveals that these two nanoclusters require different environments for the size-focusing growth process.
TL;DR: A recent review of surface imprinting can be found in this paper, where the authors present the latest advances and different approaches of surface-imprinting and their applications for microfluidic devices.
Abstract: Molecularly imprinted polymers are generated by curing a cross-linked polymer in the presence of a template. During the curing process, noncovalent bonds form between the polymer and the template. The interaction sites for the noncovalent bonds become “frozen” in the cross-linking polymer and maintain their shape even after the template is removed. The resulting cavities reproduce the size and shape of the template and can selectively reincorporate the template when a mixture containing it flows over the imprinted surface. In the last few decades the field of molecular imprinting has evolved from being able to selectively capture only small molecules to dealing with all kinds of samples. Molecularly imprinted polymers (MIPs) have been generated for analytes as diverse as metal ions, drug molecules, environmental pollutants, proteins and viruses to entire cells. We review here the relatively new field of surface imprinting, which creates imprints of large, biologically relevant templates. The traditional bulk imprinting, where a template is simply added to a prepolymer before curing, cannot be applied if the analyte is too large to diffuse from the cured polymer. Special methods must be used to generate binding sites only on a surface. Those techniques have solved crucial problems in separation science as well as chemical and biochemical sensing. The implementation of imprinted polymers into microfluidic chips has greatly improved the applicability of microfluidics. We present the latest advances and different approaches of surface imprinting and their applications for microfluidic devices.
TL;DR: An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions as mentioned in this paper, which exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures.
Abstract: An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures. The polymer nanoparticles can be used for cell imaging, which provides a potential stable fluorescent tool to monitor the distribution of drugs and bioconjugates in living cells.
TL;DR: In this paper, the state-of-the-art techniques for CO2 capture are presented and discussed, using ionic liquids instead of aqueous amine solutions overcomes the major thermodynamic issues and further advances in terms of ease of handling and sorption dynamics are obtained.
Abstract: Current state-of-the-art techniques for CO2 capture are presented and discussed. Post-combustion capture of CO2 by absorption is the technology most easily retrofitted to existing installations, but at present this is not economically viable to install and run. Using ionic liquids instead of aqueous amine solutions overcomes the major thermodynamic issues. By applying SILP technology further advances, in terms of ease of handling and sorption dynamics, are obtained. Initial experimental studies showed that ionic liquids such as tetrahexylammonium prolinate, [N6666][Pro], provide a good candidate for CO2 absorption using SILP technology. Thus a solid SILP absorber comprised of 40 wt% [N6666][Pro] loaded on precalcined silica quantitatively takes up about 1.2 mole CO2 per mole of ionic liquid in consecutive absorption-desorption cycles in a flow-experiment performed with 0.09 bar of CO2 (9% CO2 in He).
TL;DR: In this paper, a review of the morphology impact of Co3O4, CeO2 and Fe2O3 nanomaterials in catalytic reactions, together with related literature on morphology-dependent nanocatalysis of metal oxides, demonstrate the importance of tuning the shape of oxide-nanocatalysts for prompting their activity, selectivity and stability.
Abstract: The design and fabrication of solid nanomaterials are the key issues in heterogeneous catalysis to achieve desired performance. Traditionally, the main theme is to reduce the size of the catalyst particles as small as possible for maximizing the number of active sites. In recent years, the rapid advancement in materials science has enabled us to fabricate catalyst particles with tunable morphology. Consequently, both size modulation and morphology control of the catalyst particles can be achieved independently or synergistically to optimize their catalytic properties. In particular, morphology control of solid catalyst particles at the nanometer level can selectively expose the reactive crystal facets, and thus drastically promote their catalytic performance. In this review, we summarize our recent work on the morphology impact of Co3O4, CeO2 and Fe2O3 nanomaterials in catalytic reactions, together with related literature on morphology-dependent nanocatalysis of metal oxides, to demonstrate the importance of tuning the shape of oxide-nanocatalysts for prompting their activity, selectivity and stability, which is a rapidly growing topic in heterogeneous catalysis. The fundamental understanding of the active sites in morphology-tunable oxides that are enclosed by reactive crystal facets is expected to direct the development of highly efficient nanocatalysts.
TL;DR: In this article, the authors conducted 1H NMR spectroscopy of ethanol in a large number of ionic liquids, and found an excellent correlation of the data obtained with the hydrogen acceptor properties (β-values).
Abstract: It is nowadays well-known that ionic liquids can dissolve cellulose. However, little systematic data has been published that shed light onto the influence of the ionic liquid structure on the dissolution of cellulose. We have conducted 1H NMR spectroscopy of ethanol in a large number of ionic liquids, and found an excellent correlation of the data obtained with the hydrogen acceptor properties (β-values). With this tool in hand, it is possible to distinguish between cellulose-dissolving and non-dissolving ionic liquids. A modulating effect of both, the anion of the non-dissolving ionic liquid and its cation was found in solubility studies with binary ionic liquid mixtures. The study was extended to other non-dissolving liquids, namely water and dimethylsulfoxide, and the effect of the cation was also investigated.
TL;DR: The synthesis of a new type of BODIPY compound that carries an azido group on the 3-position of the pyrrole core that can be used in the cell imaging applications.
Abstract: Borondipyrromethenes (BODIPY) are a class of fluorescent dyes whose fluorescence quantum yields are generally high and independent of the solvent. In this paper, we report the synthesis of a new type of BODIPY compound that carries an azido group on the 3-position of the pyrrole core. The azido group quenches the fluorescence of the dye due to its weak electron-donating effect. The fluorescence of the BODIPY dye can be switched on after reacting with alkynes via a Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction. We further demonstrate that this azido-BODIPY compound can be used in the cell imaging applications.
TL;DR: A series of novel thio-triazole derivatives including thiols, thioethers and thiones as well as some corresponding triazolium compounds were conveniently and efficiently synthesized from commercially available halobenzyl halides and thiosemicarbazide showing effective antibacterial and antifungal activities.
Abstract: A series of novel thio-triazole derivatives including thiols, thioethers and thiones as well as some corresponding triazolium compounds were conveniently and efficiently synthesized from commercially available halobenzyl halides and thiosemicarbazide. All the new compounds were characterized by 1H NMR, 13C NMR, FTIR, MS and HRMS spectra. Their antibacterial and antifungal activities in vitro were evaluated against four Gram-positive bacteria, four Gram-negative bacteria and two fungi by two-fold serial dilution technique. The preliminary bioassay indicated that some prepared triazoles exhibited effective antibacterial and antifungal activities. Especially, 3,4-dichlorobenzyl triazole-thione and its triazolium derivatives displayed the most potent activities against all the tested strains.
TL;DR: In this article, it was found that the dissolution of ZnO was remarkably enhanced in some imidazolium chloride by the addition of urea, and the solubility of zinc in 1:1 [Amim]Cl/urea mixture was as high as 8.35 wt% at 373.2 K.
Abstract: To solve the inherent disadvantages in conventional processes for electrodeposition of zinc, it’s necessary to develop more high-efficiency and environmentally friendly electrolytes. In this work, it was found that the dissolution of ZnO was remarkably enhanced in some imidazolium chloride by the addition of urea, and the solubility of ZnO in 1:1 [Amim]Cl/urea mixture was as high as 8.35 wt% at 373.2 K. Electrochemical measurements showed that zinc could be readily electrodeposited from the solutions of ZnO. Bright, dense and well adherent zinc coatings with good purity were obtained from 0.6 M solution of ZnO in 1:1 [Amim]Cl/urea at 323.2–343.2 K. It’s expected that the solutions of ZnO in imidazolium chloride/urea mixtures have the potential to replace the traditional electrolytes, especially toxic zinc chloride-based ones for zinc electroplating, as well as preparation of zinc materials.
TL;DR: In this paper, low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, and tested for their ability to remove cephalexin from aqueous solutions.
Abstract: Cephalexin’s traces within pharmaceutical effluents have toxic impact toward ecological and human health. Low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, and tested for their ability to remove cephalexin from aqueous solutions. Oxidization with H2O2 showed negative effect on the cephalexin sorption, whereas HNO3 oxidization improved the adsorption. The cephalexin adsorption isotherms on the native and HNO3 oxidized carbons correlated well with the Freundlich equation while their kinetics followed the pseudo-second order model. The removal of cephalexin by the native and HNO3 oxidized carbons was found to be most favored at low ionic strength and strong acidic conditions. Based on the thermal and FTIR analyses, the interaction mechanisms of the interaction between cephalexin and the carbons were proposed. Electrostatic attraction, hydrophobic interaction and chemical bonding with surface functional groups were demonstrated as primary mechanisms for cephalexin removal. The nitrogen functionalities on the carbon surface were considered to be an important factor affecting the adsorption process.
TL;DR: In this paper, the chemical and physical effect of ultrasound and summarized the ultrasonic effect on crystallization of inorganic nanomaterials were discussed and discussed in terms of the sonolysis of water and cavitation-induced microjet impact and shockwave.
Abstract: A clear understanding of the nucleation, growth, coarsening, and aggregation processes of nanomaterials is necessary to enable the preparation of highly controlled nanostructures. Among wet chemical synthetic methods, ultrasound-assisted preparation has become an important tool in material science. The formation and crystal growth mechanism under ultrasound is special compared with other wet chemical synthetic routes. In this review, we discussed the chemical and physical effect of ultrasound and summarized the ultrasonic effect on crystallization. The sonolysis of water and the cavitation-induced microjet impact and shockwave are the two key factors in the sonochemical formation of inorganic nanomaterials. The ultrasonic-assisted Ostwald ripening and oriented attachment processes have been reviewed for the possible crystal growth mechanisms in the fabrication of inorganic nanostructures.
TL;DR: In this article, the impact of diamines and solvent properties on the surface NH2 density was assessed by using X-ray photoelectron spectroscopy (XPS) and colorimetric analysis.
Abstract: The aminolysis can effectively introduce primary amine (−NH2) groups onto polyester materials, enabling a variety of subsequent surface biofunctionalization reactions. However, less attention has been paid to the basic knowledge of aminolysis reaction in terms of reaction kinetics and its influences on materials properties. In this study, taking the widely used poly(ɛ-caprolactone) (PCL) as a typical example, the influences of diamines and solvent property on the surface −NH2 density are firstly assessed by using X-ray photoelectron spectroscopy (XPS) and colorimetric analysis. Results show that smaller diamine molecules and nonpolar alcohols could accelerate the reaction. The reaction kinetics with 1,6-hexanediamine is further investigated as a function of temperature, reaction time, and diamine concentration. During the initial stage, the reaction shows a 1st order kinetics with the diamine concentration and has an activation energy of 54.5 kJ/mol. Ionization state of the −NH2 groups on the PCL surface is determined, revealing that the pKa of −NH3
+ (<5) is much lower than that of the corresponding diamine molecules in solution. After aminolysis, surface hydrophilicity of PCL membrane is significantly enhanced, while surface elastic modulus and average molecular weight are decreased to some extent, and others such as weight, surface morphology and bulk mechanical strength are not apparently changed. The introduced −NH2 groups are found to be largely lost at 37 °C, but can be mostly maintained at low temperature.
TL;DR: In this paper, the progress and future possibilities in the emerging area of molecular spintronics are reviewed, and several schemes to include such systems into spintronic nanodevices are presented.
Abstract: We review the progress and future possibilities in the emerging area of molecular spintronics. We first provide an overview of the different transport regimes in which electronic nanodevices can operate, then briefly overview the important characteristics of molecular magnetic materials that can be useful for application in spintronics and we eventually present several schemes to include such systems into spintronic nanodevices. We hightlight the importance of a chemical approach to the area, and in the last section we showcase some approaches to the creation of hybrids made of carbon nanostructures and molecular magnets, which are gaining increasing attention.
TL;DR: A series of triethylammonium-based chlorogallate(III) ionic liquids with varied Lewis acidity was synthesized, characterized, and firstly applied to isobutane alkylation as mentioned in this paper.
Abstract: A series of triethylammonium-based chlorogallate(III) ionic liquids with varied Lewis acidity was synthesized, characterized, and firstly applied to isobutane alkylation. The [Et3NHCl]-GaCl3 with \(\chi _{GaCl_3 } \) = 0.65 displayed a potential catalytic activity for the alkylation. The addition of copper halide into the chlorogallate(III) ionic liquids dramatically enhanced the alkylation reaction. Up to 70.1% C8 selectivity and 91.3 RON were achieved with the [Et3NHCl]-GaCl3-CuCl (\(\chi _{GaCl_3 } \) = 0.65, CuCl = 5% mol) under 0.5 MPa, 900 r/min, 15 min, 288 K using the industrial C4 cut (isobutane/butene = 10). These results indicate that the chlorogallate(III) system may be used as a promising catalyst for the C4 alkylation.
TL;DR: In this paper, the authors focus on recent research progress in bio-inspired special wetting surfaces via self-assembly, such as low adhesive super hydrophobic surfaces, high adhesive superhydrophobic surface, superamphiphobic surfaces and stimuli-responsive surfaces.
Abstract: Self-assembly is the fundamental principle, which can occur spontaneously in nature. Through billions of years of evolution, nature has learned what is optimal. The optimized biological solution provides some inspiration for scientists and engineers. In the past decade, under the multi-disciplinary collaboration, bio-inspired special wetting surfaces have attracted much attention for both fundamental research and practical applications. In this review, we focus on recent research progress in bio-inspired special wetting surfaces via self-assembly, such as low adhesive superhydrophobic surfaces, high adhesive superhydrophobic surfaces, superamphiphobic surfaces, and stimuli-responsive surfaces. The challenges and perspectives of this research field in the future are also briefly addressed.