Fe3O4‐SAHPG‐Pd0 nanoparticles: A ligand‐free and low Pd loading quasiheterogeneous catalyst active for mild Suzuki–Miyaura coupling and C?H activation of pyrimidine cores

This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd⁰ nanoparticles have been immobilized in self‐assembled hyperbranched polyglycidole (SAHPG)‐coated magnetic Fe₃O₄ nanoparticles (Fe₃O₄‐SAHPG‐Pd⁰). This catalyst has been used for effective ligandless Pd catalyzed Suzuki–Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of Pd^II to Pd⁰ nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5‐b]indoles via oxidative addition/C? H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)₂ was used as the catalyst. Interestingly, the above‐mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.     

Inclusion of sulfamethoxazole in a novel CuFe2O4 nanoparticles/mesoporous silica‐based nanocomposite: Release kinetics and antibacterial activity

In this work, we aimed to improve the antibacterial activity of sulfamethoxazole (SMX) via its inclusion in a newly synthesized nanocomposite composed of CuFe₂O₄ nanoparticles and poly(vinyl alcohol)/silica‐based mesoporous materials. Characterization of this formulation using different techniques confirmed the correct synthesis and showed that this mesoporous nanocomposite had an amorphous structure with relatively high surface area of 1,620.7 m² g^?1 and mean pore diameter of 1.6576 nm. Zeta potential of the formulation was obtained to be zero which led to its higher bioavailability in comparison to pure SMX with negative zeta potential. Antibacterial property of the prepared formulation against Staphylococcus aureus and Escherichia coli was evaluated. Minimum inhibitory concentration of the SMX‐loaded mesoporous nanocomposite was considerably lower than those of pure SMX, indicating the efficient function of the mesoporous material as a delivery system. Kinetics of SMX release was also studied using zero‐order, first‐order, Higuchi, and Korsmeyer–Peppas kinetics models. According to the obtained results, the release kinetics was found to obey zero‐order model. So the possibility of sustained release of SMX from the synthesized carrier may be suggested.     

Biosynthesis,characterization, and antibacterial activity of silver nanoparticles using Rheum turkestanicum shoots extract

Research on Chemical Intermediates - Silver nanoparticles (Ag-NPs) were synthesized through a facile and “green” method, which uses the aqueous shoots extract of Rheum turkestanicum at...     

Facile pathway for synthesis of two efficient catalysts for preparation of 2-aminothiophenes and tetrahydrobenzo[b]pyrans

Research on Chemical Intermediates - We report here a new magnetically recyclable catalyst consisting of iron-substituted Keggin-type heteropolyacid (HPA) grafted on modified Fe3O4 nanoparticles....     

Lewis Acid Guests in a {P8W48} Archetypal Polyoxotungstate Host: Enhanced Proton Conductivity via Metal‐Oxo Cluster within Cluster Assemblies

Complexes made by hosts that completely surround their guests provide a means to stabilize reactive chemical intermediates, transfer biologically active cargo to a diseased cell, and construct molecular‐scale devices. By the virtue of inorganic host–guest self‐assembly, nucleation processes in the cavity of a {P₈W₄₈}‐archetype phosphotungstate has afforded a nanoscale 16‐Al^III‐32‐oxo cluster and its Ga^III analogue that contain the largest number of Al^III/Ga^III ions yet found in polyoxometalate (POM) chemistry. Interestingly, the rich Lewis acid Al^III centers within the Lewis base POM support shows an exceptional proton conductivity of 4.5×10^?2 S cm^?1 (85 °C, 70 % RH; RH: relative humidity), which is by far the highest conductivity reported among POM‐based single‐crystal proton conductors.     

C0 FE model based on HOZT for the analysis of laminated soft core skew sandwich plates: Bending and vibration

Bending and free vibration behaviour of laminated soft core skew sandwich plate with stiff laminate face sheets is investigated using a recently developed C₀ finite element (FE) model based on higher order zigzag theory (HOZT) in this paper. The in-plane displacement fields are assumed as a combination of a linear zigzag function with different slopes at each layer and a cubically varying function over the entire thickness. The out of plane displacement is considered to be quadratic within the core and constant in the face sheets. The plate theory ensures a shear stress-free condition at the top and bottom surfaces of the plate. Thus, the plate theory has all of the features required for accurate modelling of laminated skew sandwich plates. As very few element model based on this plate theory (HOZT) exist and they possess certain disadvantages, an attempt has been made to check the applicability of the refined element model. The nodal field variables are chosen in such a manner that there is no need to impose any penalty stiffness in the formulation. Refined C₀ finite element model has been utilized to study some interesting problems on static and free vibration analysis of laminated skew sandwich plates.     

Transition metal complexes of 6‐mercaptopurine: Characterization,Theoretical calculation,DNA‐Binding,molecular docking,and anticancer activity

6‐mercaptopurine (6‐MP) is used for treating various cancers and autoimmune disorders. A few examples of transition metal complexes of 6‐MP have been shown to enhance its anticancer activity, but many remain untested. We isolated five highly stable and colored metal complexes of 6‐MP and confirmed their structures by elemental analysis, spectral, and thermal techniques. Infrared (IR) spectra revealed that 6‐MP is a bidentate ligand that interacts through sulfur and pyrimidine nitrogen in a 1:2 (M:L) molar ratio. The magnetic susceptibility and electron paramagnetic resonance (EPR) spectra for the Cu(II) complex revealed an octahedral arrangement around the metal ion with strong covalent bonding. The fully optimized geometries of the metal structures obtained using density function theory (DFT)/B3LYP calculations were used to verify the structural and biological features. DNA titration revealed that the octahedral Cu(II) complex has a critical binding constant value of K_b = 8 × 105. Docking studies using three different cancer protein receptors were used to predict the biological applications of the synthesized drug‐metal complexes. Finally, cytotoxicity assays against a myeloma cancer cell line (MM) and a colon cancer cell line (Caco‐2) revealed favorable anticancer activity for the copper complex, exceeding that of the gold‐standard chemotherapeutic cisplatin.     

Simulation and demonstration of electro-optic digital logic gates based on a single microring resonator

We propose and demonstrate directed optical digital logic function which can perform several logic gates using a single microring resonator. The mode operations achieved are logic buffer, inverter, AND, NAND, OR and NOR operations. Numerical simulations, in order to analyze its static as well as dynamic responses, are carried out. In addition, we also present the fundamental numerical principles used by the simulation software in order to fully justify the simulation results. These principles are divided into three components, structure based free carrier distribution principles, change in refractive index of the waveguide and the scattering analysis on the microring resonator coupling region.