Toward enhanced catalytic activity of magnetic nanoparticles integrated into 3D reduced graphene oxide for heterogeneous Fenton organic dye degradation.

Composite Fenton nanocatalyst was prepared by water-based in situ creation of Fe3O4 nanoparticles integrated within the self-assembly 3D reduced graphene oxide (rGO) aerogel. The hybrid applied for the degradation of Acid Green 25 (AG-25) organic dye in an aqueous solution, in the presence of H2O2. By investigating the conditions that maximize the dye adsorption by the 3D composite, it was found that the pH of the solution should be adjusted between the pKa of the functional groups present on the rGO surface (carboxylic acid) and that of the dye (sulfonic acid) to promote electrostatic interactions dye-3D structure. Performed under these conditions, Fenton degradation of AG-25 in presence of H2O2 was completed in less than 30 min, including all the intermediate products, as demonstrated by MALDI-TOF-MS analysis of the aqueous solution after discoloration. Moreover, this was achieved in a solution with as high a dye concentration of 0.5 mg/mL, with only 10 mg of 3D composite catalyst, at room temperature and without additional energy input. The high performance was attributed to the creation of charge-transfer complex between rGO and Fe3O4 nanoparticles throughout covalent bond C-O-Fe, the formation of which was promoted by the in situ synthesis procedure. For the first time, up to the authors' knowledge, AG-25 degradation mechanism was proposed.

Metal-Free Regioselective Monocyanation of Hydroxy-, Alkoxy-, and Benzyloxyarenes by Potassium Thiocyanate and Silica Sulfuric Acid as a Cyanating Agent.

A novel and efficient metal- and solvent-free regioselective para-C-H cyanation of hydroxy-, alkoxy-, and benzyloxyarene derivatives has been introduced, using nontoxic potassium thiocyanate as a cyanating reagent in the presence of silica sulfuric acid (SSA). The desired products are obtained in good to high yields without any toxic byproducts.

Sonochemical synthesis of high-performance Pd@CuNWs/MWCNTs-CH electrocatalyst by galvanic replacement toward ethanol oxidation in alkaline media.

In this paper, a fast and effective method for the palladium (Pd) wire nanostructures synthesis with the great surface area through galvanic replacement reaction utilizing copper nanowires (CuNWS) as a template by the assistance of ultrasound under room temperature condition is proposed. A multifunctional catalyst with the mentioned nanostructure, Pd@CuNWs, and multi walled carbon nanotubes (MWCNTs) and chitosan (CH) as a binder was fabricated. To investigate the morphology and bulk composition of the prepared catalyst, Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), and Inductively Coupled Plasma atomic Emission Spectroscopy (ICP-AES) were utilized. Various electrochemical techniques including chronoamperometry and cyclic voltammetry were employed for the electrocatalytic activity of ethanol electrooxidation and durability in basic solution. Electrochemical catalytic activity and durability evaluation results proved that the as-synthesized Pd@CuNWs/MWCNTs-CH has a super electrocatalytic activity compared to Pd/MWCNTs and Pd/C electrocatalysts for ethanol electrooxidation. Pd@CuNWs/MWCNTs-CH catalyst demonstrated substantially enhanced performance and long-term stability for ethanol electrooxidation in the basic solution in comparison to Pd/MWCNTs and commercial Pd/C demonstrated the potential in utilizing Pd@CuNWs/MWCNTs-CH as an efficient catalyst for ethanol oxidation. Additionally, thermodynamic and kinetic evaluations revealed that the Pd@CuNWs/MWCNTs-CH catalyst has lower activation energy compared to Pd/MWCNTs and Pd/C which leads to a lower energy barrier and an excellent charge transfer rate towards ethanol oxidation. Noticeably, the Pd@CuNWs/MWCNTs-CH presented excellent catalytic activities with high peak current density which was 9.5 times more than Pd/C, and more negative onset potential in comparison to Pd/C is acquired for ethanol electrooxidation denoting synergistic effect between CuNWs/MWCNs-CH and Pd. The Pd@CuNWs/MWCNTs-CH can be considered as a valid candidate among available electrocatalysts in direct ethanol fuel cells (DEFCs).

Highly efficient synthesis of alkyl and aryl primary thiocarbamates and dithiocarbamates under metal- and solvent-free conditions.

A highly efficient, metal-free and solvent-free process is reported for the preparation of novel series of alkyl and aryl primary thiocarbamates and dithiocarbamates through the reaction of aliphatic alcohols, phenols and thiols with thiocyanate salts in the presence of 4-dodecylbenzenesulfonic acid (DBSA) as an inexpensive, readily available and amphipathic acid reagent. All reactions proceeded smoothly, and the products are obtained in good to excellent yields. Using this method, a wide range of structurally diverse primary thiocarbamates was prepared successfully.

Optically Active Poly[2-(sec-butyl)aniline] Nanofibers Prepared via Enantioselective Polymerization.

In this paper, we present a new synthetic route to produce optically active nanofibers of poly[2-(sec-butyl) aniline] (PSBA). Optically active PSBA nanofibers were produced by in situ chemical oxidative polymerization of a racemic monomer, (±)-2-sec-buthylaniline, in the presence of 1.5 M (+)- or (-)-camphor sulfonic acid (HCSA) with a monomer concentration of 0.025 M at 0 °C. The mirror-imaged circular dichroism spectra of both PSBA/(+)HCSA and PSBA/(-)HCSA show that the two polymers are optically active enantiomers, and in this condition, the chemical oxidation of 2SBA is enantioselective polymerization. The produced polymer has a uniform nanofibrillar morphology with an average diameter of 55 nm according to scanning electron microscopy and a number average molecular weight of 4680 g/mol as determined by gel permeation chromatography.

Synthesis and Application of Phosphorus/Co3O4-CuO Hybrid as High-Performance Anode Materials for Lithium-Ion Batteries.

The present study reports a novel red phosphorus (RP)/Co3O4-CuO hybrid as a high-performance anode material for lithium ion battery that was successfully synthesized by simple sol gel method and followed by facile ball milling of red phosphorus. Herein, we outstandingly improved practical application of RP anode (with its natural insulation property and rapid capacity decay in during the lithiation process) in lithium-ion batteries (LIBs) by confining nanosized amorphous RP into the Co3O4-CuO nanoparticle while RP can improve the electrochemical capacity returning and increased capacity of composite in high current density. This bonding can help maintain electrical contact, prevent to escape RP from the electrode and confirm the solid electrolyte interphase upon the large volume change of RP during cycling. As a result, by judicious usage of components in the RP/Co3O4-CuO hybrid nanostructured anode was achieved an initial Coulombic efficiency of 99.8% at a current density of 50 mA g-1 and an enhanced cycling stability (683.63 and 470.11 mAh g-1 after 60 cycles at a density of 0.1 and 1 A g1-) with interesting cycling capacity at high current density of 3 Ag1- (333.81 mAh g-1). Moreover, the composite electrode can still deliver a specific capacity of about 97.4% of initial capacity after cycling at high rates and returning to the initial current density of 0.1 A g1-.

2,2'- bipyridine coplanar with coordination square of Pd(II) nonyldithiocarbamato antitumor complex interacting with DNA in two distinct steps.

Cisplatin is one of the most effective chemotherapy drugs, and has been widely employed for more than four decades in the treatment of different forms of human tumors. In recent years, various examples of metal complex-based compounds have been used for medicinal purposes. In this context, the novel palladium(II) complex, [Pd(non-dtc)(bpy)]NO3, (non-dtc = nonyldithiocarbamate and bpy = 2,2'- bipyridine) has been synthesized and characterized by means of elemental analysis, conductivity measurements, FT-IR, 1H NMR, 13C NMR, and electronic spectroscopy studies. The 50% cytotoxic concentrations (Ic50) of this Pd(II) complex (0.53 mM) and cisplatin (154 mM) against human cell tumor line (K562) indicates its interaction with DNA of cancer cell at quite low concentration. Thus, binding characteristics of this compound to calf thymus DNA (CT-DNA) has been investigated by UV-vis absorption spectroscopy and fluorescence spectra. The exciting observation of this work in the UV-visible studies was that the Pd(II) complex exhibit two or more types of interaction with CT-DNA. Such properties have rarely been observed in the literature. This complex cooperatively binds with DNA and denatures it too. Fluorescence studies proved the intercalation mode of binding and the other modes seems to be hydrophobic and electrostatic interactions. Binding parameters and thermodynamics of the interaction with CT-DNA are also described. Finally, multifunctional interactions of [Pd(non-dtc)(bpy)]NO3 make it suitable to interact with DNA of cancer cell at quite low concentration and if it is used as anticancer agent, very low doses will be needed which may have fewer side effects.

A theoretical study of π-stacking interactions in C-substituted tetrazoles.

The π-stacking effects of benzene ring (Ben) with 1H- and 2H-tetrazole derivatives (1H-TZ-X and 2H-TZ-X) substituted at C5 (where X is Cl, COH, NO, NO2, CN, NH2, OH, OCH3, SH and H) has been investigated by the quantum mechanical calculations at the M06-2X/6-311++G** level. The results indicate the 1H-TZ-X||Ben complexes (|| donates π-stacking interaction) are more stable than 2H-TZ-X||Ben while in unstacked forms, 1H-TZ-X is less stable than 2H-TZ-X. All substituents enhance the π-stacking interaction relative to the unsubstituted ones and enhancement is higher for the electron-withdrawing substituents (EWSs). Also, investigation of the local and direct effect of substituents in stacking interaction showed that all substituents regardless of whether are electron donating or electron withdrawing have an additive effect in π-stacking interaction. Excellent correlations were found between the binding energies of the complexes and combination of substituent constant terms. The results showed that the electrostatic interaction alone is not responsible for stacking stabilization but charge penetration is important. Furthermore, analysis of aromaticity, AIM, ESP and NPA were investigated to obtain aromaticity index, non-bonding interactions, chemical reactivity and polarity (dipole moment), respectively.

Dynamic (1)H NMR spectroscopic study of the ring inversion in N-sulfonyl morpholines--studies on N-S interactions.

The effect of the exocyclic conjugation, via d-p orbital interaction and/or negative hyperconjugation (anomeric effect) of the N-S bond, on the inversion of the morpholine ring in some N-arylsulfonyl morpholines is studied by variable-temperature (1)H NMR spectroscopy in different solvents. The observed free energy barriers are 9.2-10.3 kcal mol(-1); the lower values were obtained with increasing conjugation (substituents of higher electron withdrawing power) along the series. The barrier to ring inversion of 1e was solvent independent. X-ray data of compounds 1b,d reveal the chair conformation of the six-membered ring, the flattened pyramidal orientation of the ring nitrogen atom, and the sulfonyl group in equatorial position with the plane containing the C(aryl)-S-N bond perpendicular to the plane of the benzene ring. In addition, the sulfonamide group prefers a conformation with the S-C bond antiperiplanar with respect to the nitrogen atom lone pair and the -CH(2)-N-CH(2)- moieties in staggered conformation with the S-O bonds of the SO(2) group.

Dynamic 1H NMR study of the barrier to rotation about the C-N bond in primary carbamates and its solvent dependence.

The dynamic 1H NMR study of some primary carbamates in the solvents CDCl3 and CD3COCD3 between 183 and 298 K is reported. The free energies of activation, thus obtained (12.4 to 14.3 kcal mol-1), were attributed to the conformational isomerization about the N-C bond. These barriers to rotation show solvent dependence in contrast to the tertiary analogues and are lower in free energy by ca. 2-3 kcal mol-1.