Preparation and Characterization of Bhant Leaves‐derived Nitrogen‐doped Carbon and its Use as an Electrocatalyst for Detecting Ketoconazole

In this study, the electrocatalytic characteristics of nitrogen‐doped carbon (NDC) prepared from Clerodendrum Infortunatum L leaves on a glassy carbon electrode (GCE) surface was evaluated with regards to its ability to detect the electroactive drug ketoconazole (KCZ). The NDC was prepared by carrying out a simple pyrolysis of dry powder of the leaves at 850 °C. The prepared NDC was characterized using field‐emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and Brunauer‐Emmett‐Teller analysis, and was then used as an electrode material. The performance of the electrochemical KCZ sensor with the NDC‐modified glassy carbon electrode (NDC/GCE) was found to be optimal when using PBS buffer at pH 3 and a concentration of 0.1 mg/ml of NDC in the conjugate with Nafion polymer. Under these conditions, the NDC/GCE displayed a KCZ detection limit of 3 μM and a linear dependence of its response on KCZ concentration over a wide range of KCZ concentrations from 47 μM to 752 μM (R²=0.9742). These results confirmed the potential of NDC as an electrocatalyst.     

Ceramic fuel cells using novel proton-conducting BaCe0.5Zr0.3Y0.1Yb0.05Zn0.05O3-δ electrolyte

Journal of Solid State Electrochemistry - Protonic ceramic fuel cells have become extremely interesting due to their high power output at the intermediate temperature range...     

Harnessing sun for catalyst and sensitizer free regio- and stereo-selective [2+2] cycloaddition

Presence of cyclobutane rings in bioactive natural products makes them a popular synthetic target. Most common strategy for synthesizing cyclobutanes is [2+2] cycloaddition, which is usually facilitated by using ultraviolet radiation and catalysts. Herein we report the design and synthesis of densely functionalized cyclobutanes by alleviating these drawbacks and using sunlight. Further, we identified the putative mechanism of the transformation based on kinetic, fluorescence and crystallographic studies and evaluated biological activities of the products against MCF7 cell lines. The rational design of the olefinic substrates was based on their UV–vis spectra. The generic aspect of the reaction was elucidated by the syntheses of diverse analogs of cyclobutanes. Further, crystal structures and UV–vis spectra of the olefinic partners assisted us in rationalizing the stereoselectivity of the heterodimers. We believe this energy-efficient mild approach will provide a substantial contribution to the existing repertoire of strategies to regio- and stereoselectively access cyclobutanes.     

Exploration of structural and physicochemical properties of small molecules to inhibit NMDA functionality

Structural Chemistry - The N-methyl-D-aspartate (NMDA) is the family of glutamate receptor, which is involved in controlling synaptic plasticity and memory function; but overactivation of this...     

Crystal and molecular structure of benzophenone azine: evidence for an Fe(II) carbene intermediate

Benzophenone azine crystallizes in the monoclinic space groupA2/a (No. 15) witha=16.303(3) Å,b=5.4864(2) Å,c=21.973(5) Å, =85.52(2)°,V=1959.4(8) ų, andD _calc=1.22 g cm^–3 forZ=4. The structure was solved by direct methods and refined againstF to a finalR value of 0.047. The unit cell contains four molecules of the title compound; the asymmetric unit consists of half a molecule. Despite the high crystallographic symmetry, the two halves of the molecule arenot related by a center of symmetry; instead, the molecule adopts C₂ symmetry; the molecular C₂ axis is coincident with the crystallographic twofold axis. The formation of benzophenone azine from the reaction of the iron-containing Lewis acid complex [(⁵-C₅H₅)Fe(CO)₂(THF)]⁺ [BF₄]^– and diphenyldiazomethane provides strong evidence for an Fe(II) carbene intermediate.     

X-ray structure of [(μ-H)Os3(CO)10(μ-1,8-η2-C9H6N)]

Decacarbonyl--hydrido--1,8-²-quinoline-triosmium crystallizes in the triclinic space group P with a = 7.8551(6), b = 9.1283(8), c = 16.7915(8) Å, = 74.788(2), = 88.086(2), = 66.392(3)°, V = 1062.22(13)° ų, T = 150 K, and Z = 2. The molecule consists of an Os₃ triangle with the hydride and the heterocyclic ligand bridging the same Os—Os edge. The heterocyclic ligand is coordinated through the C(8) carbon and nitrogen atoms in a new -1,8-²-bonding mode. The Os—Os distances lie in the close range 2.8837(4)–2.9034(4) Å with an average value of 2.892(7) Å.     

Construction of novel coordination polymers with simple ligands

Three different types of metal-organic polymers have been prepared by a solution diffusion process carried out at room temperature. Crystals of the copper coordination polymers [CuX(4,4′-bipy)] _n (X = Cl, Br, I) have been obtained by the reaction of 4,4′-bipyridine ligands with Cu₂X₂ fragments to yield a three-dimensional network consisting of four interlocking planar lattices. Single crystals of [Cu₂(1,2,4,5-BTC)(DMF)₂] _n (1,2,4,5-BTC = 1,2,4,5-benzene tetracarboxylate) have been grown by slow diffusion from solutions of a mixture of CuBr₂, 2,2′-dithiosalicylic acid, and sodium azide plus a mixture of 1,2,4,5-H₄BTC and 4-cyanopyridine. The complex [Co(1,3,5-BTC)(4,4′-bipy)] _n (1,3,5-BTC = 1,3,5-benzene tricarboxylate) has a 3D open framework structure involving terminal cobalt atoms plus bridging 1,3,5-BTC and 4,4′-bipyridine ligands.     

First Synthesis of Continuous Mesoporous Copper Films with Uniformly Sized Pores by Electrochemical Soft Templating

Although mesoporous metals have been synthesized by electrochemical methods, the possible compositions have been limited to noble metals (e.g., palladium, platinum, gold) and their alloys. Herein we describe the first fabrication of continuously mesoporous Cu films using polymeric micelles as soft templates to control the growth of Cu under sophisticated electrochemical conditions. Uniformly sized mesopores are evenly distributed over the entire film, and the pore walls are composed of highly crystalized Cu.     

Competing forward and reversed chain reactions in one-dimensional molecular line growth on the Si(100)-(2 x 1)-H surface

To explore the role of competing forward and reversed chain reactions in the growth of a one-dimensional (1D) molecular line on the Si(100)-(2 x 1)-H surface, controlled experiments were performed with various alkene molecules by scanning tunneling microscopy (STM) at various temperatures. It was observed that the end dangling bond (DB) of a styrene line, fabricated by a chain reaction on the Si(100)-(2 x 1)-H surface at 300 K, initiated a reverse chain reaction at 400 K, leading to the complete disappearance of the styrene line with zero-order desorption kinetics (rate constant k = 1.17 x 10-2 s-1 at 400 K). In the case of 2,4-dimethylstyrene, the reversed chain reaction was observed even at 300 K. These results suggest that the appearance of a molecular line in an STM image is determined by the rates of competing forward and reversed chain reactions at a given temperature. As predicted, 1D lines formed by the DB-initiated chain reaction of 1-hexene and 1-heptene on Si(100)-(2 x 1)-H were observed at 180 K because of the reduced desorption rate, despite the fact that those molecules showed no line growth at 300 K. These results indicate that the scope of forming 1D molecular lines on the Si(100)-(2 x 1)-H surface with various alkenes is much wider than anticipated in previous studies.     

Analytical discrimination between sources of ginseng using Raman spectroscopy

Ginseng is a widely used medicinal product that grows mainly in Korea, China and America. American ginseng is classified as an endangered species, and so the import and export of this type of ginseng is illegal in certain countries. Due to this restriction it is becoming increasingly important to be able to distinguish between different types of ginseng. FT-Raman spectroscopy has the ability to discriminate between ginseng specimens according to the country of origin and the effects of processing on the ginseng material. The ginsenoside content of ginseng differs in both conformation and concentration depending on the source of the ginseng, which means that ginseng grown in different countries should express unique spectral features. The presence or absence of these features, therefore, could indicate the geographical origin of the sample. Several spectral features were identified for a range of ginsengs, such as a peak at 980 cm(-1) that was only found in Chinese ginseng, and the different wavenumber positions of characteristic ginseng bands near 1600 cm(-1). This indicates that Raman spectroscopy can be used to pinpoint the origin of an unknown ginseng sample and that it would provide a rapid nondestructive analytical technique for formally discriminating between restricted and permitted imports.