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  • Open access
  • 54 Reads
The Investigation Effect of Ionic Liquids on Carbon Nano Tubes Dispersion
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To deepen the understanding of molecular interaction between Ionic liquids and carbon nanotube, as well as to investigate the influence of the ionic liquids tail length on the adsorption process, we report here the first detailed the adsorption and morphology of aggregates of the ionic liquids containing imidazolium ionic liquids ([Cnmim] Cl, n=10,12,14,16) on multi-walled carbon nanotube (MWCNT) surfaces. We make a comparison between the various ILs adsorptions onto MWCNT to clarify the role of the ionic liquid tail length on the adsorption process. This comparison indicates that by increasing the tail length the larger number of the ionic liquid molecules tend to adsorb onto MWCNT which can be attributed to the fact that the [Cnmim] Cl with n=16 has a longer chain. In addition, our results show that a longer chain yields the higher packed aggregates in which the IL heads are extended far into the aqueous phase, which in turn may increase the MWCNTs stabilization in aqueous suspensions.
  • Open access
  • 143 Reads
One-Pot Synthesis of Xanthones Using a Novel Copper-Based Magnetically Recoverable Nanocatalyst
The xanthone nucleus constitutes the core of an important family of natural and biologicallyactive compounds that are widespread in higher plants and microorganisms. These secondary metaboliteshave interesting pharmaceutical properties, among them anti-cancer, anti-thrombotic, anti-hypertensive,anti-bacterial, anti-tumoral, opiaceous, cytotoxic, anti-viral and anti-inflammatory activity. Standard syntheses of the xanthone skeleton typically involve multistep procedures, which generally require theintermediacy of a benzophenone or a diaryl ether, plus harsh reaction conditions, and/or strong acids ortoxic metals are often employed.Herein, we established a versatile and straightforward strategy to construct a xanthone skeleton via anintermolecular catalytic coupling of 2-substituted benzaldehydes and a wide range of phenols. For thispurpose, a novel and magnetically recoverable catalyst consisting of copper nanoparticles on nanosizedsilica coated maghemite in the presence of triphenylphospine is presented. The reaction proceedssmoothly without the need to preactivate the aldehyde carbonyl group. It can tolerate various functionalgroups and provides an efficient protocol for the generation of a small library of functionalized xanthones.The easy recyclability of the catalyst, the potential scalability of the process and the simple reactionconditions combined with the low cost of the starting materials, makes this methodology transferable topharmaceutical purposes.
  • Open access
  • 341 Reads
Synthesis and Electrochemical Redox Properties of Arylated p-Benzoquinones, Naphthoquinones and Alkylamidoalkyl-p-Benzoquinones
Quinones are known to be medicinally active compounds, where the activity resides both in the oxidative power of the molecules as well as the antioxidant behavior of the respective hydroquinones. In vivo targets of the compounds may be diverse biomolecules, including proteins, which may provide a highly polar environment for the benzoquinones at the reactive site. Against this background, a number of arylated p-benzoquinones, naphthoquinones and a series of alkylamidoalkyl-p-benzoquinones have been synthesized, and their redox behavior has been studied in the in ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, using a gold microelectrode. Diffusional coefficients and solvodynamic radii of the neutral species have been calculated for all quinone derivatives.
  • Open access
  • 112 Reads
Investigation of the Supercapacitive Performance of Modified Carbon Nanotube Materials by 1-Methyl-3-Octadecylimidazolium Bromide Ionic Liquid
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Supercapacitive properties of electrodes built from ionic liquid-Multi Walled carbon Nanotubes (MWNTs) gel electrodes have been investigated. IL/MWNTs gel was easily prepared by adding MWNTs into 1-methyl-3-octadecylimidazolium bromide ionic liquid aqueous solution, then the resulting gel deposited on Nickel foam by Electrophoretic deposition. Electrochemical characterizations were carried out by cyclicvoltammetery and impedance spectroscopy in 1M KOH aqueous solution at room temperature. The specific capacitance of this electrode (120 F/gr) was larger than those were reported for bare carbon nanotube electrodes, and pseudo faradic reactions have been detected.  
  • Open access
  • 73 Reads
Oxalate-Assisted Synthesis of Nano Cobalt Oxide
Organic ligands are widely applied in preparation of metallic complexes, and in high temperatures, can be burned and eliminted from the coordination sphere, remaining only oxide group. In a reaction between Co(NO3)2.6H2O, ammonium oxalate and F-127 as a surfactant to control the particles size, cobalt-oxalate was formed. After performing Thermal Gravimetric Analysis (TGA) to find the optimum decomposition temperature, the precipitate was calcined and the resulted nano cobalt oxide was characterized by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD). The crystalline pure and nanosized particles had the average size<40 nm.
  • Open access
  • 57 Reads
Enhancement of Flavonols Water Solubility by Cyclodextrin Inclusion Complex Formation - Case Study
The phenomenon of solubility increasing of nonpolar flavonol antioxidant – quercetin (QC) in water solutions containing β-cyclodextrin (CD) was studied. Complexation of QC by CD was investigated using phase solubility study. It allows to estimate the apparent formation constant for 1:1 host-guest complex. Additionally thermodynamic properties were evaluated as well showing spontaneous exothermic process of complex formation. Two solubility models were also employ to verify their applicability to predict QC concentration in solution. Those models included modified Apelbalt and Buchowski-Ksiazczak equations. In order to investigate the antioxidant properties of ternary systems QC/CD/water a radical scavenging activity using stable radical of DPPH was performed. Experiments indicated that antioxidant activity is temperature and CD concentration-dependent. It was shown that complexation may inhibit the radical scavenging by QC or changing the scavenging stoichiometry.
  • Open access
  • 62 Reads
Biopolymer-Supported Iron Oxide Nanocomposite: Preparation and Catalytic Application in the Synthesis of Benzodiazepine Derivatives
Nanoparticles especially coated or supported magnetic metal nanoparticles, have emerged as a new class of nanocatalyst. Simple separation from the reaction mixture is one of the advantages of these catalysts. Also they can be reused several times without any reduction in the activity. These catalysts showed not only high catalytic activity but also a high degree of chemical stability in various organic solvents. Benzodiazepines constitute an important class of heterocyclic compounds which possess a wide range of therapeutic and pharmacological properties. They are widely used as anticonvulsant, antianxiety, analgesic, sedative, anti-depressive, and hypnotic agents. Owing to their versatile applications various methods for the synthesis of benzodiazepines have been reported. One of the commonly reported methods for the synthesis of benzodiazepines is the condensation reaction between o-phenylenediamines and ketones. In continuation of our interest in the application of nanocatalysts in organic synthesis, in this work, cellulose-based nanocomposite containing high contents of Fe3O4 nanoparticles used as a catalyst in the condensation reaction between o-phenylenediamines and ketones for synthesis of benzodiazepines in good to excellent yields under mild conditions. A good correlation between the amount of surface acid sites as well as the surface morphology of the catalysts and the catalytic activity has been observed. This method has been found to be eco-friendly, simple and economical. The solid supported nanocatalyst could be recycled and reused without significant loss of its catalytic activity.
  • Open access
  • 115 Reads
A Novel Selective Synthesis of β-Isothiocyanato Ketones
A new selective two-step synthesis of β-isothiocyanato ketones from α,β-unsaturated ketones has been developed. This synthesis includes preparation of β-azidoketones with subsequent reaction of these with triphenylphosphine and carbon disulfide. This approach is especially useful for synthesis of β-unsubstituted β-isothiocyanato ketones, which are impossible to prepare with sufficient purity via commonly used procedures.
  • Open access
  • 72 Reads
Computational Study on the Structure of N-(2-Amino-benzoyl)-N'-phenyl Hydrazine
The hydrazide compound N-(2-Amino-benzoyl)-N’-phenyl hydrazine has been synthesized and characterized by 1H-NMR, 13C-NMR, IR and X-Ray determination. The molecular geometry and vibrational frequency values in the ground state have been calculated using the density functional methods HF and (B3LYP) with the 6-31G(d) and 6-31G+(d,p) basis sets. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies and chemical shift values show good agreement with experimental values.
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