2,4,6-Trichloro-1,3,5-triazine catalyzed synthesis of thiiranes from oxiranes under solvent-free and mild conditions

A simple, mild and efficient method has been developed for the synthesis of thiiranes from epoxides using a catalytic amount of 2,4,6-trichloro-1,3,5-triazine under solvent-free conditions.     

Concentration-dependent electrochemical supercapacitive performance of Fe2O3

This work reports the concentration-dependent electrochemical supercapacitor performance change of electrodeposited Fe₂O₃ thin films. Structural elucidation and morphological evolution studies are operated in the first stage and in second, electrochemical supercapacitive performances are investigated. The maximum specific capacitance of 540 F/g at 2.5 A/g in 1 M KOH is obtained. The electric parameters including specific energy, specific power and coulomb efficiency are measured using charge/discharge technique and finally, electrochemical impedance measurement is examined for knowing the internal charge transfer resistance. An equivalent circuit associated with the cell, with required parameters, is also designed.     

A simple CdS nanoparticles cascading approach for boosting N3 dye/ZnO nanoplates DSSCs overall performance

Enhanced photosensitization in presence of CdS nanoparticles is achieved in electrochemically deposited ZnO nanoplates and N3 loaded dye-sensitized solar cells. Chemically embedded CdS nanoparticles act as a sandwiching layer between ZnO nanoplates and dye molecules by overcoming current limiting serious Zn²⁺/dye insulating complex formation and CdS photo-corrosion issues. The X-ray diffraction and the scanning electron microscopy confirm the ZnO with vertically aligned nanoplates, perpendicular to the substrate surface. Amorphous CdS is monitored using electron dispersive X-ray analysis. The low and high resolution transmission electron microscope images confirm the presence of CdS nanoparticles over ZnO nanoplates which later is supported by an increase in optical absorbance and shift in band edge. About 400% increase in solar conversion efficiency with this cascade arrangement is achieved when compared with without CdS which could be fascinating while designing solid state solar cells in presence of suitable p-type layer.     

Novel synthesis of 2-arylbenzothiazoles mediated by ceric ammonium nitrate (CAN)

[reaction: see text] Cyclization of the intermediate radical formed after initial oxidative coupling between thiophenols and aromatic nitriles leads to the synthesis of a wide range of 2-arylbenzothiazoles.     

Thermodynamic functions of Ni(II) complexes with 5-(2-hydroxyphenyl)-pyrazole derivatives. A potentiometric study

Proton-ligand dissociation constants of five biologically important pyrazole derivatives, viz. [5-(2-hydroxyphenyl)-3-(pyridin-3-yl)-4-benzoyl]-pyrazol (HPPBP), [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(3-pyridinoyl)]-pyrazol (HPNPPP), [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-benzoyl]-pyrazol (HPNPBP), [5-(2-hydroxyphenyl)-3-phenyl-4-(3-pyridinoyl)]-pyrazol (HPPPP), and [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(2-furoyl) pyrazol (HPNPFP) and metal ligand stability constants of their Ni(II) complexes in 70% (v/v) dioxane-water and 0.1 M KNO₃ were determined at 298.15, 303.15, and 308.15 K by potentiometric method. Thermodynamic functions, such as, free energy change (ΔG ^○), enthalpy change (ΔH ^○) and entropy (ΔS ^○) change for dissociation and complex formation have been estimated form temperature dependence of proton-ligand and metal-ligand stability constants and interpreted in terms of feasibility of these processes.     

Aldose reductase inhibitory, anti-cataract and antioxidant potential of selected medicinal plants from the Marathwada region, India

The water, ethanol and chloroform extracts of selected plants such as Adhatoda vasica (L.) (Acanthaceae), Caesalpinia bonduc (L.), Cassia fistula (L.) (Caesalpiniaceae) and Biophytum sensitivum (L.) (Oxalidaceae) were evaluated for rat lens aldose reductase inhibitory (RLAR) potential, anti-cataract and antioxidant activities. All the samples inhibited the aldose reductase considerably and exhibited anti-cataract activity, while C. fistula (IC(50), 0.154 mg mL(-1)) showed significant RLAR inhibitory activity as compared to the other tested samples, and was further found to be more effective in maintaining sugar-induced lens opacity in the rat lens model. The antioxidant potential of plant extracts was determined using DPPH (2,2-diphenyl-1-picryl hydrazine), hydroxyl (OH), nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) scavenging activities, along with determination of reducing power, ferrous ion chelating ability and inhibition of polyphenol oxidase (PPO). The extracts of the tested plant showed significant free radical scavenging activities and inhibited the activity of enzyme PPO, a model oxidising enzyme. The plant samples were found to possess considerable amounts of vitamin C, total polyphenols and flavonoids.     

Palladium catalyzed ligand-free Suzuki cross-coupling reactions of benzylic halides with aryl boronic acids under mild conditions

A highly efficient Suzuki cross-coupling reaction between benzylic halides and aryl boronic acids using palladium chloride as catalyst in acetone:water (3:1) as the solvent system has been developed. High yields of products, mild reaction conditions and short reaction times in the absence of ligand are important features of this method.     

Temperature dependence of density, viscosity, ultrasonic velocity, and other properties of substituted pyrazoles in acetone-water mixtures

The density, viscosity and ultrasonic velocity of some substituted pyrazoles viz. 5-(2-hydroxyphenyl)-3-(pyridin-3-yl)-4-benzoylpyrazol, 5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(3-pyridinoyl)-pyrazol, 5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-benzoylpyrazol and 5-(2-hydroxyphenyl)-3-phenyl-4-(3-pyridinoyl)-pyrazole have been measured in 70: 30 (vol/vol) acetone-water mixture at 298, 303, 308, and 313 K for 0.01 mol dm^?3 concentration of pyrazoles. The acoustical parameters such as adiabatic compressibility (??_s), relative association (R _A), specific acoustic impedance (Z), apparent molar volume (?_v), apparent molar adiabatic compressibility (?_K), and intermolecular free length (L _f) were calculated from the experimental densities and velocities. The changes in acoustical properties have been used to interpret the molecular interactions in solutions. The activation energies of viscous flow of pyrazole solutions were determined from the data of viscosity at different temperature.