Immobilization of nickel ions onto the magnetic nanocomposite based on cross‐linked melamine groups: Effective heterogeneous catalyst for N‐Arylation of Arylboronic acids

A new magnetic heterogeneous catalyst was synthesized by immobilization of nickel ions onto a cross‐linked polymeric nanocomposite composed of cyanuric chloride, ethylenediamine and functionalized magnetic nanoparticles. The resulting nitrogen rich support was capable of adsorbing large amounts of nickel ions (1.20 mmol g^?1). The synthesized catalyst was characterized using AAS, TEM, FT‐IR, EDX, TGA, SEM, BET and XRD techniques. The performance of the prepared catalyst was investigated in the C‐N coupling of arylamines with aryl boronic acids. The reaction was carried out under a mild condition and good to moderate to good yields of products was obtained using only 5.0 mol% of the catalyst. The catalyst was easily recovered and reused for at least 7 times without any significant loss of its activity.     

A innovative switchable polarity solvent,based on 1,8‐diazabicyclo‐[5.4.0]‐ undec‐7‐ene and decanol was prepared for enrichment of aluminum in biological sample prior to analysis by flame atomic absorption spectrometry

A novel switchable solvent (SS) extraction methodology has been used for the enrichment of aluminium (Al) in acid‐digested blood samples of patients with neurological disorders before proceeding to flame atomic absorption spectrometry. 1,8‐Diazabicyclo[5.4.0]undec‐7‐ene and decanol in combination made a SS which reversibly changes from hydrophobic (nonpolar) to hydrophilic (polar) according to switch‐on and switch‐off phenomena in aqueous medium by exposure to anti‐solvent trigger (CO₂). The SS polar micro‐emulsion was switched on by bubbling CO₂, and switched off by heating from 40 to 70°C with exposure to N₂ gas. The changes obtained in the structure and physical properties of the SS due to switching from lower polarity to higher polarity were investigated using Fourier transform infrared spectroscopic analysis. The SS was effectively analysed as an extractive medium for hydrophobic chelate of Al with 3,5,7,2,4‐pentahydroxyflavone (morin) and extracted in SS. Then hydrophobic enriched Al‐morin‐SS was treated with 1.0 M HNO₃ and CO₂ purging at various time intervals, switch to a miscible polar hydrophilic monophase state. The SS was easily recycled up to six times for further enrichment process. For the developed method, various parameters were optimized such as pH, volume of chelating reagent, CO₂ purging time and pressure, and rate of heating. Under favourable conditions, enhancement factor and limit of detection were observed as 25 and 0.47 μg l^?1, respectively, for 10 ml of samples/standards solution. The accuracy of the developed method was determined using certified reference material (SRM 3101a), with a standard addition procedure. The method was used for the pre‐concentration of Al in blood samples of patients with neurological disorders.     

1,3,4-Triarylpyrazoles Containing 2-Thioxoimidazolidinones and Different Fused Systems: Synthesis and Antimicrobial Activity

Russian Journal of General Chemistry - A group of new analogs of 1,3,4-trisubstituted pyrazoles functionalized 2-thioxoimidazolidinones and fused heterocyclic systems are synthesized. Their tests...     

Suzuki–Miyaura coupling catalyzed by palladium nanoparticles biosynthesized using Glycyrrhiza glabra as reducing and stabilyzing agent

An unprecedented environmentally friendly method has been developed for the synthesis of palladium nanoparticles supported on Glycyrrhiza glabra. The synthesized nanoparticles were utilized in Suzuki–Miyaura reaction between different aryl halides and aryl bronic acid in aqueous media. This heterogeneous catalyst can be reused and recycled repeatedly more than five times with only slight loss of its initial catalytic efficiency. This reaction carrid out under atmospheric pressure with high efficiency, unique and simple work‐up procedure and excellent yields.     

Catalytic application of sulfonic acid‐functionalized titana‐coated magnetic nanoparticles for the preparation of 1,8‐dioxodecahydroacridines and 2,4,6‐triarylpyridines via anomeric‐based oxidation

We have developed green, efficient and powerful protocols for the preparation of 2,4,6‐triarylpyridines and 1,8‐dioxodecahydroacridines in the presence of Fe₃O₄@TiO₂@O₂PO₂(CH₂)₂NHSO₃H as a sulfonic acid‐functionalized titana‐coated magnetic nanoparticle catalyst under mild and solvent‐free reaction conditions. These protocols furnished the desired products in short reaction times with good to high yields (20–40 min and 80–86% in the case of 2,4,6‐triarylpyridines; 15–90 min and 80–93% in the case of 1,8‐dioxodecahydroacridines). The final step of the mechanistic route in the synthesis of 2,4,6‐triarylpyridines proceeds via an anomeric‐based oxidation. Also, the nanomagnetic core–shell catalyst can be recycled and reused in both cases of the scrutinized one‐pot multicomponent reactions with high turnover number and turnover frequency.     

Synthesis and characterization of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles: A heterogeneous,reusable and magnetically separable catalyst for the solvent‐free synthesis of 2‐amino‐4H‐chromene derivatives

An efficient and facile method was used for the synthesis of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles. The structure of this nanoparticle was characterized by scanning electron microscopies, X‐ray diffraction, energy‐dispersive X‐ray, Fourier transform infrared spectroscopies and vibrating sample magnetometry. Then, this compound was used as a reusable heterogeneous catalyst for green synthesis of 2‐amino‐4H‐chromene derivatives via one‐pot three‐component reactions. This novel material showed great catalytic performance and the reactions which were carried out by this catalyst showed good to excellent yields. Besides, the catalyst could easily be separated from the reaction mixture by using an external magnetic field and it was stable enough to reuse several times without any significant reduction in the yield of reactions. Eco‐friendliness, high purity of the desired products, short reaction time and easy workup procedure can be mentioned as the other advantages of this method.     

Green synthesis of silver nanoparticles using Eucalyptus comadulensis leaves extract and its immobilization on magnetic nanocomposite (GO-Fe3O4/PAA/Ag) as a recoverable catalyst for degradation of organic dyes in water

The magnetically recyclable graphene oxide-Fe₃O₄/polyallylamine (PAA)/Ag nanocatalyst was prepared via a green route using Eucalyptus comadulensis leaves extract as both reducing and stabilizing agent. The catalytic activity of this nanocatalyst was investigated for the reduction reaction of methylene blue and methyl orange in the presence of NaBH₄ in aqueous medium at room temperature. The prepared nanocatalyst was characterized by different methods such as Fourier transformed infrared spectroscopy, X-ray diffraction, scanning electron microscopy–energy dispersive X–ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, transmission electron microscopy, and UV–visible spectroscopy. The results show that graphene oxide/PAA/Ag nanocatalyst has good activity and recyclability, and can be reused several times without major loss of activity in the reduction process. The apparent rate constants of the methyl orange (MO) and methylene blue (MB) were calculated to be 0.077 s⁻¹ (3 mg of catalyst) and 0.15 s⁻¹ (2 mg of catalyst), respectively.     

Antibacterial,DFT and molecular docking studies of Rh(III) complexes of Coumarinyl‐Thiosemicarbazone nuclei based ligands

Coumarinyl thiosemicarbazone derivatives (1E)‐1‐(1‐(2‐oxo‐2H‐chromen‐3‐yl)ethylidene)thiosemicarbazide (OCET), (1E)‐1‐(1‐(6‐bromo‐2‐ oxo‐2H‐chromen‐3‐yl)ethylidene)thiosemicarbazide (BOCET) and 1‐(1‐(3‐oxo‐3H‐benzo[f]chromen‐2‐yl)ethylidene)thiosemicarbazide (NOCET) and their Rh(III) complexes were synthesized, the characterization was carried out by elemental analysis, IR, UV–Visible, mass, magnetic measurement and molar conductance techniques. Data interpretation of the Rh(III) complexes indicates that the ligands of coumarinyl thiosemicarbazone derivatives were formed in stoichiometric ratios as 1:2 (metal: ligand). The studied ligands act as a bidentate ligand by using both azomethine nitrogen and thiol sulphur as monoanion center of donation. The theoretical conformational structure analyses were performed using density functional theory for ligands and complexes at B3LYP functional with 6‐31G(++)d,p basis set for ligands and LANL2DZ basis set for complexes. The charge distribution within the ligands and its Rh(III) complexes was calculated using Mulliken population analysis of (MPA) and natural population analysis (NPA). The antibacterial activity of the prepared compounds was tested against some types of Gram positive and negative bacteria. Molecular docking investigation proved that, the ligands and complexes had interesting interactions with active site amino acids of ribosyltransferase (code: 3GEY).     

Logarithmic correction to BMSFT entanglement entropy

Using Rindler method we derive the logarithmic correction to the entanglement entropy of a two dimensional BMS-invariant field theory (BMSFT). In particular, we present a general formula for extraction of the logarithmic corrections to both the thermal and the entanglement entropies. We also present a CFT formula related to the logarithmic correction of the BTZ inner horizon entropy which results in our formula after taking appropriate limit.     

Oxidative amidation of benzyl alcohol,benzaldhyde, benzoic acid styrene and phenyl acetylene catalyzed by ordered mesoporous HKUST‐1‐Cu: Effect of surface area on oxidative amidation reaction

HKUST‐1‐Cu synthesized in the presence and absence of P‐123 trough solvotermal method. After characterization using some different microscopic and spectroscopic techniques such as XRD, FT‐IR, SEM, ICP, BET and TEM its catalytic activity was investigated in the oxidative coupling of benzyl alcohol, benzaldhyde, benzoic acid, styrene and phenyl acetylene with N,N‐dialkylformamides for the preparation of N,N‐dimethylformamides. Different derivatives of tertiary amides were synthesized in moderate to good yields in the presence of just ~0.28 mol% of this catalytic system. Reusability of the synthesized catalysts was examined and catalysts were reusable for 8 times without significant decrease in optimized conditions.