Electric field effect in diluted magnetic insulator anatase Co: TiO2

An external electric field induced reversible modulation of a room temperature magnetic moment and coercive field is achieved in an epitaxial and insulating thin film of dilutely cobalt-doped anatase TiO2. This first demonstration of an electric field effect in any oxide-based diluted ferromagnet is realized in a high quality epitaxial heterostructure of PbZr(0.2)Ti(0.8)O(3)/Co: TiO(2)/SrRuO(3) grown on (001) LaAlO3. The observed effect, which is about 15% in strength in a given heterostructure, can be modulated over several cycles. Possible mechanisms for electric field induced modulation of insulating ferromagnetism are discussed.     

Preparation and structural characterisation of methoxybis(trimethylsilyl)silyl potassium and its condensation product

Depending on the conditions the reaction of tris(trimethylsilyl)methoxysilane (1) with potassium tert-butoxide either in benzene and in the presence of 18-crown-6 or in THF gives either the crown ether adduct of potassium-methoxybis(trimethylsilyl)silane (2), or 2-methoxytetrakis(trimethylsilyl)disilanyl potassium (3).     

A New Chromogenic Spray Reagent for Detection and Identification of Monocrotophos

JPC – Journal of Planar Chromatography – Modern TLC - Sensitive and selective detection of monocrotophos after TLC is possible by use of vanillin as reagent. The product from alkaline...     

Thin-Layer Chromatographic Detection of Selected Pyrethroids with p-Benzoquinone Reagent

JPC – Journal of Planar Chromatography – Modern TLC - Cypermethrin is frequently encountered in poisoning cases in India. In TLC, the compound can be detected by spraying the plate with...     

On‐line 2D‐LC‐ESI/MS/MS determination of rifaximin in rat serum

A highly sensitive and selective on‐line two‐dimensional reversed‐phase liquid chromatography/electrospray ionization–tandem mass spectrometry (2D‐LC‐ESI/MS/MS) method was developed and validated to determine rifaximin in rat serum by direct injection. The 2D‐LC‐ESI/MS/MS system consisted of a restricted access media column for trapping proteins as the first dimension and a Waters C₁₈ column as second dimension using 0.1% aqueous acetic acid:acetonitrile as mobile phase in a gradient elution mode. Rifampacin was used as an internal standard. The linear dynamic range was 0.5–10 ng/mL (r² > 0.998). Acceptable precision and accuracy were obtained over the calibration range. The assay was successfully used in analysis of rat serum to support pharmacokinetic studies. Copyright © 2009 John Wiley & Sons, Ltd.     

Sodium Bisulfite as an Efficient and Inexpensive Catalyst for the One-pot Synthesis of 2,4,5-Triaryl-1<Emphasis Type="Italic">H</Emphasis>-imidazoles from Benzil or Benzoin and Aromatic Aldehydes

Summary. 2,4,5-Triaryl-1H-imidazoles were efficiently synthesized from benzoin or benzil, ammonium acetate, and aromatic or heteroaromatic aldehydes in the presence of sodium bisulfite as catalyst. The present protocol offers significant improvements for the synthesis of 2,4,5-triaryl-1H-imidazoles with regard to yield of products, simplicity in operation, and cheap catalyst.     

Determination of Band Structure Parameters and the Quasi‐Particle Gap of CdSe Quantum Dots by Cyclic Voltammetry

Band structure parameters such as the conduction band edge, the valence band edge and the quasi‐particle gap of diffusing CdSe quantum dots (Q‐dots) of various sizes were determined using cyclic voltammetry. These parameters are strongly dependent on the size of the Q‐dots. The results obtained from voltammetric measurements are compared to spectroscopic and theoretical data. The fit obtained to the reported calculations based on the semi‐empirical pseudopotential method (SEPM)—especially in the strong size‐confinement region, is the best reported so far, according to our knowledge. For the smallest CdSe Q‐dots, the difference between the quasi‐particle gap and the optical band gap gives the electron–hole Coulombic interaction energy (J_e1,h1). Interband states seen in the photoluminescence spectra were verified with cyclic voltammetry measurements.     

Greener approach: Ionic liquid [Et3NH][HSO4]-catalyzed multicomponent synthesis of 4-arylidene-2-phenyl-5(4H)oxazolones under solvent-free condition

We have developed simple, greener, safer multicomponent synthesis series of 4-arylidene-2-phenyl-5(4H) oxazolones 4(a-r) catalyzed by Bronsted acid ionic liquid as triethylammonium hydrogen sulfate [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate with excellent yields (90–99%). The protocol offers economical, environmentally benign, solvent-free conditions, and recycle–reuse of the catalyst and easily available starting as benzoyl chloride 1, amino acid 2 and a variety of aldehydes 3. The cyclization followed by condensation of benzoyl chloride, amino acid, and a variety of aldehydes catalyzed by ILs [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate. The final products were confirmed by their characterization data such as FTIR, ¹H-NMR, ¹³C-NMR, Mass, high-resolution mass spectra and were compared with its reported method.     

m-Chloroperbenzoic acid-oxchromium (VI)-mediated cleavage of 2,4,5-trisubstituted oxazoles

An array of 2-substituted-4,5-diphenyloxazoles were found to be cleaved to triacylamines and diacylamines (imides) using a reagent system composed of m-chloroperbenzoic acid (MCPBA) and 2,2′-bipyridinium chlorochromate (BPCC). The 2-alkyl-4,5-diphenyloxazoles give imides (38–60%) as the predominant cleavage product while the 2-aryl-4,5-diphenyloxazoles give triacylamines (44–71%). Two mechanisms involving intermediates such as cyclic endoperoxides or oxachromacycles were proposed. An application of the oxidative cleavage to the multi-step synthesis of (±)-phoracantholide I seco acid is detailed.     

Boric acid catalyzed convenient synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines in aqueous media

A one-pot three-component condensation of an aldehyde, malononitrile, and thiophenol has been achieved by conventional and ultrasound method. The reaction has been catalyzed by boric acid in aqueous medium. This protocol afforded corresponding 2-amino-3,5-dicarbonitrile-6-thio-pyridines in shorter reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents.