Unexpected regio- and stereoselective [4 + 3] cycloaddition reaction of azomethine ylides with benzylidene thiazolidinediones: synthesis of pharmacologically active spiroindoline oxazepine derivatives and theoretical study

Molecular Diversity - An unexpected regio- and stereoselective [4?+?3] cycloaddition reaction of azomethine ylides with 5-benzylidenethiazolidine-2,4-diones has been successfully...     

Preconcentration and spectrophotometric determination of low concentrations of malachite green and leuco-malachite green in water samples by high performance solid phase extraction using maghemite nanoparticles

A novel and sensitive extraction procedure using maghemite nanoparticles (γ-Fe₂O₃) modified with sodium dodecyl sulfate (SDS), as an efficient solid phase, was developed for removal, preconcentration and spectrophotometric determination of trace amounts of malachite green (MG) and leuco-malachite green (LMG). Combination of nanoparticle adsorption and easily magnetic separation was used to extraction and desorption of MG and LMG. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. Maghemite nanoparticles were prepared by co-precipitation method and their surfaces were modified by SDS. The size and properties of the produced maghemite nanoparticles was determined by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and BET analysis. MG and LMG became adsorbed at pH 3.0. LMG was oxidized to MG by adsorption on maghemite nanoparticles. The adsorbed MG was then desorbed and determined spectrophotometrically. The calibration graph was linear in the range 0.50-250.00 ng mL⁻¹ of MG and LMG with a correlation coefficient of 0.9991. The detection limit of the method for determination of MG was 0.28 ng mL⁻¹ and the relative standard deviation (R.S.D.) for 10.00 and 50.00 ng mL⁻¹ of malachite green was 1.60% (n = 3) and 0.86% (n = 5), respectively. A preconcentration factor of 50 was achieved in this method. The Langmuir adsorption capacity (q_max) was found to be 227.3 mg g⁻¹ of the adsorbent. The method was applied to the determination of MG in fish farming water samples.     

高有机可溶性聚酰胺负载磷钨酸(PW_(12)/PA):合成1,3,5-三芳基-2-吡唑啉衍生物的高效催化剂(英文)

A novel compound constructed from polyoxometalate (H3PW12O40,PW12) and poly(amidoamine) (PA) was prepared at room temperature in an aqueous solution by an impregnation method.A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by the reaction between chalcone and phenylhydrazine in the presence of the title compound,PW12/PA,in high yields.The structures of the compounds obtained were determined by IR and 1H NMR spectra.     

Surface modification of glassy carbon electrode with the functionalized carbon nanotube for ultrasensitive electrochemical detection of risperidone

Risperidone (RIS), one of the typical antipsychotics drugs, originally approved to be used for the mental illness treatment, especially schizophrenia, bipolar disorder, autism and major depression. In the present study, different carbon nanostructures including functionalized multi-walled carbon nanotubes (F-MWCNTs), carbon nanoparticles, nanodiamond-graphite and reduced graphene oxide were employed for modification of the surface of glassy carbon electrode (GCE) for ultrasensitive detection of RIS. The most significant increase in the anodic peak current of RIS was observed on F-MWCNTs-modified electrode (compared to the other modified electrodes and bare GCE). The influence of different experimental parameters such as pH of the buffered solutions, the amount of the modifier and time and potential of the accumulation was optimized by monitoring the LSV responses toward RIS for the selected modified electrode. A wide linear dynamic range of 0.04–7 µM with a low detection limit of 12 nM was obtained. The results exhibit an acceptable performance of the proposed electrode for determination of RIS in the pharmaceutical and clinical preparations.     

N-Doped Hybrid Graphene and Boron Nitride Armchair Nanoribbons As Nonmagnetic Semiconductors with Widely Tunable Electronic Properties

Russian Journal of Physical Chemistry A - The electronic and chemical properties of N-doped hybrid graphene and boron nitride armchair nanoribbons (N-doped a-GBNNRs) in comparison with graphene...