P2O5/SiO2‐Catalyzed One‐Pot Synthesis of Amides from Ketones via Schmidt Reaction under Microwave Irradiation in Dry Media

A facile and efficient method for the preparation of amides from ketones by the Schmidt reaction is described for the first time using P₂O₅/SiO₂ and sodium azide under solvent‐free microwave irradiation. Advantages of this procedure are selectivity, good yields, a simple operation, short reaction time, and solvent‐free conditions.     

Molecular Dynamics Simulation of the Ionic Liquid 1-n-Butyl-3-Methylimidazolium Methylsulfate [Bmim][MeSO4]: Interfacial Properties at the Silica and Vacuum Interfaces

Molecular dynamics simulations are done to investigate the structure and dynamics of a thin [Bmim][MeO₄] film in contact with a hydroxylated silica surface on one side and with vacuum on the other. An examination of the microscopic structure of ionic liquid (IL) film shows that strong layered anionic/cationic structures are formed at both interfaces. At the silica interface, the imidazolium rings are closer to the silica surface (compared to anions) and are coplanar with it. At the vacuum interface, the charged imidazolium ring more concentrates in the interior of the film, but the butyl side chain stretches out toward the vacuum interface. While there exists an excess concentration of the cations at the silica interface, at the vacuum interface an excess concentration of anions (dissolved in the butyl chain) is found. The influence of the interface on the dynamical properties is shown to depend on their time scales. A short-time dynamical property, such as hydrogen bond formation is not noticeably perturbed at the interface. In contrary, long-time properties such as ion-pair formation/rupture and translation of ions across the film are largely decelerated at the silica interface but are accelerate at the vacuum interface. Our findings indicate that the structural relaxation time of ion-pairs, is comparable to diffusion time scale in the IL film. Therefore, ion-pairs are not stable species; the IL is composed of short-lived ion-pairs and freely diffusing ions. However, the structural relaxation times of ion-pairs is still long enough (comparable to the time scale of diffusion) to conclude that correlated motions of counterions influence the macroscopic properties of IL, such as diffusion and ionic conductivity. In this respect, we have shown that correcting the Nernst-Einstein equation for the joint translation of ion-pairs considerably improves the accuracy of calculated ionic conductivities.     

Separation and determination of ciprofloxacin in seawater,human blood plasma and tablet samples using molecularly imprinted polymer pipette‐tip solid phase extraction and its optimization by response surface methodology

By synthesizing a molecular imprinted polymer as an efficient adsorbent, ciprofloxacin was micro‐extracted from seawater, human blood plasma and tablet samples by pipette‐tip micro solid phase extraction and determined spectrophotometrically. Response surface methodology was applied with central composite design to build a model based on factors affecting on microextraction of ciprofloxacin; including volume of eluent solvent, number of extraction cycles, number of elution cycles, and pH of sample. Other factors that affect extraction efficiency, such as type of eluent solvent, volume of sample, type, and amount of salt were optimized with one‐variable‐at‐a‐time method. Under optimum extraction condition, pH of sample solution was 7.0, volume of eluent solvent (methanol) was 200 µL, volume of sample solution was 10 mL, and the number of extraction and elution cycles was five and seven, respectively, amount of Na₂SO₄ (as salt) and MIP (as sorbent) were optimized at 150 and 2 mg, respectively. The linear range of the suggested method under optimum extraction factors was 5–150 µg/L with a limit of detection of 1.50 µg/L for the analyte. Reproducibility of the method (as relative standard deviation) was better than 7%.     

Recent developments of advanced numerical heat transfer in porous media

Journal of Thermal Analysis and Calorimetry -     

Theoretical calculation of simple and doped CNTs with the potential adsorption of various ions for water desalination technologies

Structural Chemistry - In this work, the interactions between simple carbon nanotubes (CNTs) and doped carbon nanotubes (DCNTs; with sulfur, boron, aluminum, silicon, phosphorus, or nitrogen) as...     

Phosphorus‐containing polyamide Mg(OH)2 nanocomposite coating on surface of poly(vinyl chloride) thin film: Study on thermal stability,flammability, and mechanical properties

Surface of poly(vinyl chloride) (PVC) thin films was coated using DOPO‐based polyamide (DBPA) coating and DBPA/Mg(OH)₂ nanocomposites (DBPN) coating by dip‐coating process. For this purpose, a new DOPO‐based dicarboxylic acid (DBDA) was synthesized and used for preparation of DBPA and organically surface modification of Mg(OH)₂ nanoparticles. The effects of DBPA and DBPN coatings on the morphology, thermal stability, combustion, and mechanical properties of PVC were investigated. The uniform dispersion of Mg(OH)₂ nanoparticles (nano‐MDH) and organically coating manner on the surface of the PVC films were confirmed by ATR‐IR spectroscopy, X‐ray diffraction (XRD), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray, and elemental mapping. From thermal gravimetry analysis (TGA) results, the 10 mass% loss temperature (T₁₀) increased from 268°C to 272°C in PVC coated with DBPA‐containing 10 mass% of modified Mg(OH)₂ (MMH). Also the char residue, first and second mass loss temperatures of all PVC coated were increased compared with the neat PVC film. According to microscale combustion calorimetry (MCC) results, the peak of heat release rate (pHHR) and total heat release (THR) were decreased from 128 ± 2 to 69 W/g and 12 ± 1 to 4 ± 2 KJ/g for PVC film coated with DBPA‐containing 10 mass% of MMH, compared with the neat PVC. From tensile test results, tensile strength was increased from 31.78 ± 0.8 to 39.64 ± 0.9 MPa for PVC coated with polyamide‐containing 5 mass% of MMH compared with the neat PVC.     

Incorporation of two‐dimensional nanomaterials into silk fibroin nanofibers for cardiac tissue engineering

Mimicking the extracellular matrix to have a similar nanofibrous structure regarding electrical conductivity and mechanical properties would be highly beneficial for cardiac tissue engineering. The molybdenum disulfide, MoS₂, and reduced graphene oxide, rGO, nanosheets are two‐dimensional nanomaterials which can be considered as great candidates for enhancing the electrical and mechanical properties of biological scaffolds for cardiac tissue engineering applications. In this study, MoS₂ and rGO nanosheets were synthesized and incorporated into silk fibroin nanofibers, SF, via electrospinning method. Then, the human iPSCs transfected with TBX‐18 gene, TBX18‐hiPSCs, were seeded on these scaffolds for in vitro studies. The MoS₂ and rGO nanosheets were studied by Raman spectroscopy. After incorporation of the nanosheets into SF nanofibers, the associated characterizations were carried out including scanning electron microscopy, transmission electron microscopy, water contact angle, and mechanical test. Furthermore, SF, SF/MoS₂, and SF/rGO scaffolds were used for in vitro studies. Herein, the scaffolds exhibited acceptable biocompatibility and considerable attachment to TBX18‐hiPSCs confirmed by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyl tetrazolium bromide, MTT, assay, and scanning electron microscopy. Also, the real‐time PCR and immunostaining studies confirmed the maturity and upregulation of cardiac functional genes, including GATA‐4, c‐TnT, and α‐MHC in the SF/MoS₂ and SF/rGO scaffolds compared with the bare SF one. Therefore, the reinforcement of these SF‐based scaffolds with MoS₂ and rGO endues them as a suitable candidate for cardiac tissue engineering.     

Design,in silico,one-pot synthesis,and biological evaluations of novel bis-urea analogs

Research on Chemical Intermediates - The structure of urea has received special attention due to its biological activity. A new and efficient one-pot three-component reaction for the synthesis of...     

Production, nano-purification, radiolabeling and biodistribution study of [140Nd] 5,10,15,20-tetraphenylporphyrin complex as a possible imaging agent

[¹⁴⁰Nd] labeled 5,10,15,20-tetraphenylporphyrin ([¹⁴⁰Nd]-TPP) as a tumor–avid complex with a β-emitting radionuclide for evaluating its potential for target tumor therapy is reported. This complex was prepared using freshly prepared [¹⁴⁰Nd] NdCl₃ (purified by amino functionalized MCM-41 nano resin and commercial cation exchanger resins) and 5,10,15,20-tetraphenylporphyrin (H₂TPP).Stability of the complex was investigated in final formulation and human serum for 24 h and the partition coefficient was calculated. The biodistribution of the labeled compound in vital organs of Swiss mice bearing fibro sarcoma tumor was studied using scarification studies and positron emission tomography imaging up to 4 h.