β-Cyclodextrin conjugated magnetic nanoparticles for diazepam removal from blood

β-CD conjugated magnetic nanoparticles that serve as a hemoadsorbent for diazepam removal are fabricated. The diazepam is arrested by the conjugated β-CD and then the adsorbed diazepam is efficiently removed by an external magnetic field. These particles have potential applications in hemoperfusion or separation of other toxins and drugs.     

Ion recognition by 1,2,3-triazole moieties synthesized via “click chemistry”

1,2,3-Triazole-based ligands obtained through copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) have been exploited in vast array of research domains owing to the stitching of simpler molecules through a needle of Cu(I) catalyst. The numerous reports on ion(s) detection capabilities of synthesized 1,4-disubstituted 1,2,3-triazole ligands using absorption and fluorescence spectroscopy are accessible. This review enlists substituted 1,2,3-triazole-based sensor probes, since 2010, synthesized selectively by CuAAC, having the ability to sense either a single ion or multiple ions under specific set of conditions along with their detection limits. The review also apprehends the different techniques and sensing mechanisms involved in the detection of ions by chemosensor probes.     

Design of phosphonate analogs of short peptides by “click” chemistry

Methods were developed for the first time for the modification of the natural neuropeptides Ile–Gly–Leu and Leu–Gly–Leu simultaneously with the phosphonate moiety and the triazole ring or solely with the triazole ring by means of click chemistry. All of the peptidomimetics synthesized were isolated as a mixture of diastereomers and were characterized by spectroscopic methods.

     

Functionalization of cellulose via ATRP and “click” chemistry to construct hydrophobic filter paper for oil/water separation

Cellulose - Cellulosic materials show great superiority in oil/water separation owing to abundance, low cost, renewability and biodegradability. Herein, silylated cellulose graft copolymer...     

A 1,4-diphenyl-1,2,3-triazole-based β-turn mimic constructed by click chemistry

A series of 1,4-diphenyl-1,2,3-triazole-incorporated amide derivatives have been designed and prepared. X-ray crystallographic and (1D and 2D) (1)H NMR studies reveal that these compounds fold into stable U-shaped conformations driven by three-center intramolecular C-H···O hydrogen-bonding formed between the triazole C-5 H atom and the two ether O atoms. Such folded structures make this 1,4-diphenyl-1,2,3-triazole skeleton a good candidate to be used as β-turn mimic. To prove this, the formation of a β-hairpin structure induced by this β-turn motif has been further demonstrated.     

Poly[(mercaptopropyl)methylsiloxane](PMMS)-based antibacterial polymer coatings prepared by a two-step sequential thiol–ene click chemistry

Poly[(mercaptopropyl)methylsiloxane](PMMS)-based antibacterial polymer coatings have been prepared through a two-step sequential thiol–ene click chemistry utilizing 1-allyl-3-decylimidazolium bromide(ADIm) as antibacterial monomer and triallyl cyanurate(TAC) as the crosslinker. These films with different content of ADIm were characterized by thermogravimetric analysis(TGA), dynamic mechanical analysis(DMA) and pencil hardness. It was found that the mechanical and thermal properties of these films were largely influenced by the content of ADIm in the films. Films with imidazolium bromide groups displayed excellent antimicrobial activity against Staphylococcus aureus with 100% killing efficiency.     

Efficient cellulose solubilization by a combined cellulosome-β-glucosidase system

The cellulosome, the multienzyme complex of the cellulase system ofClostridium thermocellum, that mediates the solubilization of insoluble cellulose, is strongly inhibited by the major end product, cellobiose. By combining a purified β-glucosidase fromAspergillus niger with the cellulosome, accumulated cellobiose was hydrolyzed thereby resulting in a dramatic enhancement (up to 10-fold) of cellulose degradation. The observed enhancement was expressed both in the rate and degree of solubilization of microcrystalline cellulose, compared with that observed for the unsupplemented cellulosome. Near-complete conversion of cellulose to glucose could be obtained from dense substrate suspensions (up to at least 200 g/L).     

Physical and optical properties of organo-modified silica nanoparticles prepared by sol–gel

A comparative study on the physical and optical properties of silica nanoparticles prepared by sol–gel has been carried out. Post-modification of as-synthesized silica nanoparticles produced organo-functionalized silica nanoparticles slightly increased in size (~20%) and relatively high aggregation. However, in situ method produced sixfold bigger functionalized particles with good dispersion and less aggregation. Higher organic content was observed for in situ modified nanosilica, leading to a higher surface hydrophobicity that improved compatibility and dispersion in preparation of silica-polymer nanocomposite. Furthermore, in situ and post-modified nanosilica demonstrated a distinct optical activity, photoluminescence and UV compared to the unmodified nanoparticles.     

Calcination temperature-dependent morphology of photocatalytic ZnO nanoparticles prepared by an electrochemical–thermal method

ZnO nanoparticles (NPs) with tunable morphologies were synthesized by a hybrid electrochemical–thermal method at different calcination temperatures without the use of any surfactant or template. The NPs were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, dynamic light scattering, thermogravimetry–differential thermal analysis, scanning electron microscope and N₂ gas adsorption–desorption studies. The FT-IR spectra of ZnO NPs showed a band at 450 cm^?1, a characteristic of ZnO, which remained fairly unchanged at calcination temperatures even above 300 °C, indicating complete conversion of the precursor to ZnO. The products were thermally stable above 300 °C. The ZnO NPs were present in a hexagonal wurtzite phase and the crystallinity of ZnO increased with an increasing calcination temperature. The ZnO NPs calcined at lower temperature were mesoporous in nature. The surface areas of ZnO NPs calcined at 300 and 400 °C were 51.10 and 40.60 m² g^?1, respectively, which are significantly larger than commercial ZnO nanopowder. Surface diffusion has been found to be the key mechanism of sintering during heating from 300 to 700 °C with the activation energy of sintering as 8.33 kJ mol^?1. The photocatalytic activity of ZnO NPs calcined at different temperatures evaluated by photocatalytic degradation of methylene blue under sunlight showed strong dependence on the surface area of ZnO NPs. The ZnO NPs with high surface area showed enhanced photocatalytic activity.     

The properties of nickel aluminate nanoparticles prepared by sol–gel and impregnation methods

Nickel aluminates were prepared by sol–gel and impregnation methods and calcined at 1100 °C. The sol–gel made samples were prepared with different amounts of nickel (Ni/Al molar ratio equal to 0, 0.25, 0.5, and 0.75) and aging times (24 and 48 h). The samples were characterized by X-ray diffraction, induced couple plasma, nitrogen physisorption, transmission and scanning electron microscopy, and ammonia temperature programmed desorption (NH₃-TPD). In the sol–gel made samples, only the NiAl₂O₄ structure of nickel aluminate was defined, while for impregnation, NiAl₁₀O₁₆ was formed as well. The sol–gel made samples had low specific surface areas (7.7–12.4 m²/g), but a sample prepared by impregnation method had higher specific surface area (67.2 m²/g). The surface acidity density decreased by increasing the amount of nickel and was the lowest for impregnation method.     

Synthesis and characterization of nitrogen-doped TiO2 nanoparticles prepared by sol–gel method

The N-doped TiO₂ has been synthesized by sol?Cgel method, using titanium isopropoxide, isopropanol and an aqueous solution of ammonia with ratio 2:1:10. The concentrations used for the NH₃ aqueous solution were 3, 7, 10 and 15?%. The samples have been analysed by X-ray diffraction, electron microscopy (SEM and TEM) thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), micro-Raman spectroscopy and diffuse reflectivity. TEM, SEM, DSC and TGA showed that the morphology is influenced by the presence of N^3? ions but not by the concentration of the solution. Instead reflectance gave us a relation between values of the energy gap and the concentration of N^3? ions: the gap between valence and conduction band lowers as the concentration of NH₃ in the starting solution increases. From these results we can say that the properties of the material have been tuned by doping with nitrogen ions because the particles absorb more light in the visible range, and this is important for photovoltaic and photocatalytic applications.     

Structural stability and electrochemical properties of Gd-doped ZrO2 nanoparticles prepared by sol–gel

Cubic, tetragonal and monoclinic Gd-doped zirconia nanoparticles with nominal composition Gd_xZr_1?xO₂ in the range 0 ≤ x ≤ 0.2, were prepared by annealing dried gels of Gd-containing zirconia at temperatures over the range between 450 and 1,300 °C. The synthesized zirconia-based nanoparticles with increased gadolinium load were characterized by X-ray powder diffraction, infrared and Raman spectroscopies, and transmission electron microscopy. The stabilization of the crystalline forms of Gd-doped ZrO₂ solid solutions depends on the amount of Gd dopant and the annealing temperature. For low Gd loads in Gd_xZr_1?xO₂ being x < 0.05, the tetragonal form is the single phase up to 1,100 °C, whereas the monoclinic is the crystalline form detected up to 1,300 °C. Within the range of compositions 0.05 ≤ x < 0.1, is the tetragonal the only stabilized zirconia crystalline structure over the whole range of temperature up to 1,300 °C. For higher Gd-contents, in the range 0.1 ≤ x ≤ 0.2, is the cubic zirconia form the only stable phase for the whole range of annealing temperatures. Solid-state electrochemistry of the gadolinium-doped zirconia performed by the voltammetry of microparticles approach allowed distinguishing different electrochemical answers of Gd cation associated with slightly different local coordination surrounding of cations. Enantioselective electrocatalytic effect of monoclinic Gd-doped ZrO₂ on the oxidation of l-(+)-tartaric acid and d-(?)-tartaric was also studied.     

Preparation of new poly(ester triazole) and poly(amide triazole) by “click chemistry”

New dialkynyl monomers containing furan and ester or amide units were prepared via three step reactions from ethyl furan-2-carboxylate. Their click polymerization with either poly(ethylene glycol) diazide or poly(tetrahydrofuran) diazide catalyzed by Cu(I) led to corresponding amorphous poly(ester triazole) and poly(amide triazole) with molecular weights in the range of (7–11) × 10³ and with glass transition temperatures in the range of ?35 and ?19°C. The temperature at 5% wt loss (T ₁₀), determined from TGA of polyazomethines were in the range 345–365°C indicating their good thermal stability.     

119Sn Mössbauer spectroscopy of Sn–O nanoparticles prepared by levitation-jet aerosol synthesis

Sn–O nanoparticles were prepared by levitation-jet aerosol synthesis and found to exhibit ferromagnetic behavior. X-ray powder diffraction analysis and ¹¹⁹Sn Mössbauer spectroscopy confirmed these nanoparticles consist of β-Sn, SnO and SnO₂ phases. The maximum specific magnetization was observed for nanoparticles containing the SnO/SnO₂ interface.     

Structural and optical characterization of Ag-doped TiO2 nanoparticles prepared by a sol–gel method

Undoped and silver-doped TiO₂ nanoparticles (Ti_1?x Ag _x O₂, where x?=?0.00?C0.10) were synthesized by a sol?Cgel method. The synthesized products were characterized by X-ray diffraction (XRD), particle size analyzer (PSA), scanning electron microscope (SEM), and UV?CVisible spectrophotometer. XRD pattern confirmed the tetragonal structure of synthesized samples. Average crystallite size of synthesized nanoparticles was determined from X-ray line broadening using the Debye?CScherrer formula. The crystallite size was varied from 8 to 33?nm as the calcination temperature was increased from 300 to 800?°C. The incorporation of 3 to 5% Ag⁺ in place of Ti⁴⁺ provoked a decrease in the size of nanocrystals as compared to undoped TiO₂. The SEM micrographs revealed the agglomerated spherical-like morphology of particles. SEM, PSA, and XRD measurements show that the particles size of the powder is in nanoscale. Optical absorption measurements indicated a red shift in the absorption band edge upon silver doping. Direct allowed band gap of undoped and Ag-doped TiO₂ nanoparticles measured by UV?CVis spectrometer were 3.00 and 2.80?eV, respectively, at 500?°C.     

Heat treatment effects in oxygen-doped β-Li3PS4 solid electrolyte prepared by wet chemistry method

Journal of Solid State Electrochemistry - For advanced all-solid-state lithium batteries, the solid electrolyte is one of the most critical components that significantly affect battery performance....     

Synthesis and characterization of poly(ɛ-caprolactone-co-ethylene glycol) star-type amphiphilic copolymers by “click” chemistry and ring-opening polymerization

Abstract

The synthesis of poly(?-caprolactone-co-ethylene glycol) AAB star-type amphiphilic copolymers were carried out by use of a “click” chemistry reaction to block propargyl polyethylene glycol (propargyl-PEG) to terminally azide poly(?-caprolactone) (PCL-N₃). For this purpose, propargyl-PEG was synthesized by the reaction of PEGs (3000?Da, 2000?Da, 1500?Da, and 1000?Da) and propargyl chloride. Terminally chloride poly(?-caprolactone) (PCL-Cl) was carried out by means of ring-opening polymerization (ROP) of ?-caprolactone (CL) and 3-chloro-1,2-propanediol. Synthesis of PCL-N₃ was obtained by the chemical interaction of PCL-Cl and sodium azide. By reacting propargyl-PEG and PCL-N₃, the star-type amphiphilic copolymers were obtained. The characterization of products was accomplished by using multiple instruments including ¹H-NMR, FT-IR, GPC, TGA, contact angles, and elemental analysis techniques.