An Efficient Green Synthesis of a New Class of α‐Aminophosphonates under Microwave Irradiation Conditions in the Presence of PS/PTSA

The present work focuses on the study of catalytic activity of polystyrene‐supported p‐toluenesulfonic acid (PS/PTSA) and the synthesis of α‐aminophosphonates from the Kabachnik–Fields (KF) reaction under microwave irradiation in solvent‐free conditions. Recently, the catalytic activity of PS/PTSA was tested with good yields. This procedure is the simplest, most straightforward, environment friendly method for the synthesis of α‐aminophosphonates from simple to different substituted aldehyde substrates. Furthermore, this catalyst can be recovered and reused without loss of its catalytic activity.     

Increasing hydrodynamic efficiency by reducing cross-beam energy transfer in direct-drive-implosion experiments

A series of experiments to determine the optimum laser-beam radius by balancing the reduction of cross-beam energy transfer (CBET) with increased illumination nonuniformities shows that the hydrodynamic efficiency is increased by ～35%, which leads to a factor of 2.6 increase in the neutron yield when the laser-spot size is reduced by 20%. Over this range, the absorption is measured to increase by 15%, resulting in a 17% increase in the implosion velocity and a 10% earlier bang time. When reducing the ratio of laser-spot size to a target radius below 0.8, the rms amplitudes of the nonuniformities imposed by the smaller laser spots are measured at a convergence ratio of 2.5 to exceed 8 μm and the neutron yield saturates despite increasing absorbed energy, implosion velocity, and decreasing bang time. The results agree well with hydrodynamic simulations that include both nonlocal and CBET models.     

Facile xenon capture and release at room temperature using a metal-organic framework: a comparison with activated charcoal

Two well-known metal-organic frameworks (MOF-5, NiDOBDC) were synthesized and studied for facile xenon capture and separation. Our results indicate that NiDOBDC adsorbs significantly more xenon than MOF-5, and is more selective for xenon over krypton than activated carbon.     

Synthesis and antiosteoclast activity of Di(1‐oxo/thioxoperhydro‐1λ5‐[1,3,2] diazaphospholo [1,5‐a]pyridine‐1‐yl) (4‐substituted phenyl) boronates

A new family of di(1‐oxo/thioxoper‐hydro‐1λ⁵‐[1,3,2]diazaphospholo[1,5‐a]pyridine‐1‐yl)(4‐substituted phenyl) boronates ( 4a – j ) has been synthesized in a two‐step process. A reaction of (±)‐piperidin‐2‐yl‐methanamine ( 1 ) phosphoryl/phosphorothioyl chloride in the presence of triethylamine in dry tetrahydrofuran formed the intermediate monochloride ( 2 ), which on condensation with p‐substituted phenylboronic acids ( 3a – j ) afforded the titled compounds ( 4a – j ). They were characterized by elemental, IR, ¹H, ¹³C, ³¹P NMR, and mass spectral analyses. All these compounds showed moderate to high antiosteoclast and osteoblast activity. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:247–253, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21010     

Preparation and Characterization of CuCrO2 Prepared by Solid State Reaction Method

Recently, delafossite materials have captured the interest of numerous researchers due to their unique characteristics of p-type conductivity and transparency. These materials exhibit promising potential in various applications such as photovoltaics, sensors, and transparent electronics. This paper presents a detailed account of the preparation of CuCrO₂ delafossite via the solid-state reaction method. The structural properties of the sample are analyzed using XRD which confirms rhombohedral crystal structure with R-3m space group. The optical band gap was determined to be 3.39 eV through UV-visible spectroscopy. The morphology is studied using Laser Confocal scanning optical microscopy and the estimated grain size is found to be within the range of 7 µm.     

Geometry and nonlinear evolution equations

We briefly review the nonlinear dynamics of diverse physical systems which can be described in terms of moving curves and surfaces. The interesting connections that exist between the underlying differential geometry of these systems and the corresponding nonlinear partial differential equations are highlighted by considering classic examples such as the motion of a vortex filament in a fluid and the dynamics of a spin chain. The association of the dynamics of a non-stretching curve with a hierarchy of completely integrable soliton-supporting equations is discussed. The application of the surface embeddability approach is shown to be useful in obtaining such connections as well as exact solutions of some nonlinear systems such as the Belavin-Polyakov equation and the inhomogeneous Heisenberg chain.     

Quantitative determination of tri-n-butyl phosphate by fluorescent X-ray spectrometry through inorganic association with an actinide

Tri-n-butyl phosphate (TBP) continues to be the most widely used solvent in nuclear fuel extraction, refining and reprocessing units for the extraction of actinides and their separation from fission products. An X-ray fluorescence spectrometric method (XRFS) for the determination of TBP content with an X-ray detectable element is presented. The method involves formation of an ion association complex of uranium with TBP-kerosene mixture in 3M nitric acid. The analytes uranium and bromine used as internal ratio elements in organic extract are excited by a primary X-ray beam from a rhodium tube. The solvent concentration is determined from the ratioed characteristic intensities of uranium and bromine. The procedure permits the determination of organic solvent in the range 0.5 to 5.0% with a relative standard deviation of 0.1%.     

One-pot regio- and stereoselective cyclization of 1,2,n-triols

A simple and efficient process to cyclize triols containing a 1,2-diol functionality with a pendant hydroxyl group is presented. The one-pot procedure converts the 1,2-diol into an ortho ester in situ, which upon treatment with a Lewis acid generates a cyclic acetoxonium intermediate. This intermediate is subsequently trapped by the pendant hydroxyl group to generate a cyclic ether. The stereochemistry of the 1,2-diol is transferred to the product with complete fidelity (inversion at the site of cyclization), and the reaction proceeds with high regioselectivity. The process is akin to the Lewis acid-catalyzed intramolecular ring-opening of epoxides with hydroxyl groups yielding cyclic ethers of various sizes with regio- and stereochemical control.     

SH3-like fold proteins are structurally conserved and functionally divergent

The folding space for all the protein sequences is limited. Therefore it was observed that many proteins, whose sequences are not related, have similar fold characteristics. The fold databases like SCOP and CATH have classified various protein folds. However, in-depth analysis of the functional features of these folds was not done. We analyzed about twenty unique SH3-like folded proteins in their structural environment and functional characteristics. From our analysis it is apparent that the SH3-like folds could carry out various functions by modulation of loops and the functional region is restricted to one side of a particular sheet helped by two or three loops. The functions vary from oligonucleotide-binding to peptide-binding and other ligand binding. Although certain degree of sequence similarity was observed among the SH3-fold proteins, the similarity was restricted to the beta-strand regions of the proteins.     

Selective reduction of alkenes, α,β-unsaturated carbonyl compounds, nitroarenes, nitroso compounds, N,N-hydrogenolysis of azo and hydrazo functions as well as simultaneous hydrodehalogenation and reduction of substituted aryl halides over PdMCM-41 catalyst under transfer hydrogen conditions

Chemoselective reductions of alkenes, α,β-unsaturated carbonyl compounds, nitro and nitroso compounds, N,N-hydrogenolysis of azo and hydrazo functions as well as simultaneous reduction and hydrodehalogenation of substituted aryl halides, including bulkier substrates, were achieved by catalytic transfer hydrogenation (CTH) using mesoporous PdMCM-41 catalyst. The yields were practically unaffected upon recycling of the catalyst. Further, the CTH process is accomplished without affecting the reduction of any other reducible functional group.