Organometallic polymer-functionalized Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles as a highly efficient and eco-friendly nanocatalyst for C–C bond formation

A magnetically recoverable biopolymer-based nanocatalyst was prepared through the covalent immobilization of a chitosan-bound 2-hydroxynaphthaldehyde Pd complex on the surface of superparamagnetic nanoparticles. The nanocatalyst was characterized by FTIR, X-ray powder diffraction and scanning electron microscopy, revealing an average particle size of 70 nm. The catalyst shows high thermostability by thermogravimetric analysis. Estimated Pd loading by inductively coupled plasma atomic emission analysis was found to be 0.348 mmol g^?1. The nanocatalyst exhibits excellent catalytic performance in Suzuki couplings of various aryl halides with phenylboronic acid, and Heck reactions of iodo- and bromoarenes with butylacrylate. The catalyst can be easily separated from the reaction mixture with an external magnet and reused consecutively four times without significant loss in activity.     

Modification of Tao–Mason equation of state to ionic liquids

In our previous paper, we extended the Tao and Mason equation of state (TM EOS) to refrigerant fluids, using the speed of sound data. Here, we predict the equation of state for ionic liquids (ILs). The considered ILs are [Bmim][PF₆], [C₂mim][NtF₂], [C₃mim][NtF₂], [C₆mim][NtF₂], [C₇mim][NtF₂], [C₂mim][EtOSO₃], [Bmim][MeSO₄], [Bmim][OcSO₄], and [C₄mim][dca]. The equation of state consists of three temperature-dependent parameters: the second virial coefficient, a constant for scaling the softness of repulsive force, and an effective hard-sphere diameter equivalent to the van der Waals co-volume. The second virial coefficients of ILs are scare and there is no accurate potential energy function to allow their theoretical calculation. In this work, the second virial coefficient have been calculated using corresponding states correlation based on temperature and density at normal boiling point. The other two parameters of the equation of state can be calculated using a scaling rule. Analysis of our predicted results shows that the Tao?CMason equation of state is capable of accurately predicting the density of ILs at any temperature and pressure. The overall average absolute deviation densities for 1,633 data points are 2.05%. Also, the density of ILs obtained from the TM EOS has been compared with those calculated from vdW?CCS?C?? and Peng?CRobinson (PR) equation of state. Our results are in favor of the preference of the TM EOS over the two other equations of state. The overall average absolute deviation for 1,633 data points calculated by vdW?CCS?C?? and PR equation of state are 6.63% and 12.19%, respectively.     

Coumarins: Facile and Expeditious Synthesis via Keggin‐Type Heteropolycompounds under Solvent‐Free Condition

Different Keggin‐type heteropolycompounds were used in Pechmann reaction to obtain biologically active coumarins. Effect of solvent, catalyst loading, and molar ratios of substrates was studied to introduce the best reaction condition. The optimized reaction condition was extended to Pechmann reaction of methylacetoacetate with various monohydric and polyhydric phenols. This rapid procedure afforded structurally diverse coumarins with high to excellent yields. Short reaction times, simple work‐up, and mild reaction conditions were advantages of this method. The optimized catalysts were reusable for four runs.     

Graphene oxides as support for the synthesis of nickel sulfide–indium oxide nanocomposites for photocatalytic,antibacterial and antioxidant performances

NiS (nickel sulfide)–In₂O₃ (indium oxide) nanostructures and NiS–In₂O₃ decorated on graphene oxide (GO) were demonstrated by ultrasonic/hydrothermal method. The structural study demonstrates the preparation of bixbyite and hexagonal phase of In₂O₃ and NiS for all of the synthesized catalysts. The band gap of the synthesized catalyst was determined to be in the range of 2.30–3.00 eV. A morphological evaluation by field emission scanning electron microscopy of NiS–In₂O₃ decorated on graphene oxide shows support for the NiS–In₂O₃ on the graphene oxide layer. Different test parameters were performed to study the phase and morphology. The particle sizes of the In₂O₃, NiS–In₂O₃ and NiS–In₂O₃/GO nanocomposites were 56.0, 62.0 and 66.0 nm, respectively. The photocatalytic performance of NiS–In₂O₃/GO nanocomposites was examined for the degradation of methylene blue dye under a UV lamp. The prepared sample shows 98.25% photocatalytic degradation within 40 min and at pH 9. With the presence the NiS and GO, the photo-degradation capacities of In₂O₃ and NiS–In₂O₃ are improved owing to the low band gap being calculated in UV–vis DRS analysis. The high ratio of NiS causes the highest photocatalytic properties of NiS–In₂O₃ nanocomposites owing to the enhancement of charge separation efficiency and generation of hydroxyl radicals. This study presents a facile and low-cost method to prepare highly active NiS–In₂O₃/GO nanocomposites. The antibacterial data indicate the significant properties of NiS–In₂O₃/GO nanocomposites for this study.     

Dynamical and structural symmetries for the highest Landau levels on the <Emphasis Type="Italic">AdS</Emphasis><Subscript>2</Subscript>

The aim of the paper is to use the recurrence relations with respect to both indices of the associated Legendre functions for the extraction of the Dirac quantization condition and dynamical symmetry group U(1, 1) corresponding to the highest Landau levels on the hyperbolic plane with uniform magnetic field B. Irreducible representations of the su(2) algebra are obtained by the ladder differential operators which change B by 1/2 unit and mode number by one unit. Two different classes of the irreducible representations of SU(1, 1) with the even and odd boson numbers 2B − 1/2 are extracted for the Bargmann indices 1/4 and 3/4, respectively. Finally, we show that shape invariance symmetry is realized by the ladder operators which shift only the magnetic field B by 1/2 unit.     

The Neuroprotective Role of Polydatin: Neuropharmacological Mechanisms,Molecular Targets,Therapeutic Potentials,and Clinical Perspective

Neurodegenerative diseases (NDDs) are one of the leading causes of death and disability in humans. From a mechanistic perspective, the complexity of pathophysiological mechanisms contributes to NDDs. Therefore, there is an urgency to provide novel multi-target agents towards the simultaneous modulation of dysregulated pathways against NDDs. Besides, their lack of effectiveness and associated side effects have contributed to the lack of conventional therapies as suitable therapeutic agents. Prevailing reports have introduced plant secondary metabolites as promising multi-target agents in combating NDDs. Polydatin is a natural phenolic compound, employing potential mechanisms in fighting NDDs. It is considered an auspicious phytochemical in modulating neuroinflammatory/apoptotic/autophagy/oxidative stress signaling mediators such as nuclear factor-κB (NF-κB), NF-E2–related factor 2 (Nrf2)/antioxidant response elements (ARE), matrix metalloproteinase (MMPs), interleukins (ILs), phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt), and the extracellular regulated kinase (ERK)/mitogen-activated protein kinase (MAPK). Accordingly, polydatin potentially counteracts Alzheimer’s disease, cognition/memory dysfunction, Parkinson’s disease, brain/spinal cord injuries, ischemic stroke, and miscellaneous neuronal dysfunctionalities. The present study provides all of the neuroprotective mechanisms of polydatin in various NDDs. Additionally, the novel delivery systems of polydatin are provided regarding increasing its safety, solubility, bioavailability, and efficacy, as well as developing a long-lasting therapeutic concentration of polydatin in the central nervous system, possessing fewer side effects.     

Synthesis of the dopamine D2/D3 receptor agonist (+)-PHNO via supercritical fluid chromatography: preliminary PET imaging study with [3-C]-(+)PHNO

Carbon-11 labeled (+)-4-[1-¹¹C]propyl-3,4,4a,5,6,10b-hexahydro-2H-naphtho[1,2-b][1,4]oxazin-9-ol ([1-¹¹C]-(+)-PHNO) is a dopamine D₃-preferring agonist radiopharmaceutical used for medical imaging by positron emission tomography (PET). We report the synthesis of (+)-PHNO using supercritical fluid chromatography for enantiomeric resolution of its norpropyl derivative, HNO, followed by propylation. (+)-HNO was used to prepare the radiolabeling precursor, (+)-trans-4-acetyl-9-triisopropylsilyloxy-2,3,4a,5,6,10b-hexahydro-4H-naphth[1,2b][1,4]oxazine, in 12 steps. Modifications to the labeling procedure were made to ensure consistent preparation of [3-¹¹C]-(+)-PHNO via [¹¹C]CH₃I. A preliminary PET imaging study was carried out with this tracer in an attempt to image dopamine receptors in brown adipose tissue (brown fat) in vivo.     

Approach of the associated Laguerre functions to the su(1,1) coherent states for some quantum solvable models

Using second‐order differential operators as a realization of the su(1,1) Lie algebra by the associated Laguerre functions, it is shown that the quantum states of the Calogero‐Sutherland, half‐oscillator and radial part of a 3D harmonic oscillator constitute the unitary representations for the same algebra. This su(1,1) Lie algebra symmetry leads to derivation of the Barut‐Girardello and Klauder‐Perelomov coherent states for those models. The explicit compact forms of these coherent states are calculated. Also, to realize the resolution of the identity, their corresponding positive definite measures on the complex plane are obtained in terms of the known functions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009     

Design and Application of a Non‐enzymatic Sensor Based on Metal‐organic Frameworks for the Simultaneous Determination of Carbofuran and Carbaryl in Fruits and Vegetables

A novel, stable and sensitive non‐enzymatic sensor was developed with metal‐organic frameworks (MOFs) that have attracted great attention in electrochemical sensors applications in recent years. The pore structures of MIL (Fe)‐101 and MIL (Fe)‐53 are the families of MOFs that were constructed via a simple solvothermal procedure. The 35MIL‐101(Fe)‐reduced graphene oxide nanocomposite has been used for modification of glassy carbon electrode for the determination of carbofuran (CBF) and carbaryl (CBR). The porosity of the composites increased the voltammetric responses significantly for CBF and CBR in a mixed solution that makes the simultaneous determination of both carbamate pesticides possible. Characterization of MIL (Fe)‐101 and MIL (Fe)‐53 were performed with FT‐IR, XRD, BET and SEM. Finally, the introduced sensor under the optimal conditions showed low detection limits of 1.2 and 0.5 nM within the linear ranges of 5.0–200.0 nM and 1.0–300.0 nM for CBF and CBR, respectively. The non‐enzymatic sensor was successfully used to monitoring of carbamates residue in vegetable and fruit samples.