Efficient One‐Pot Four‐Component Synthesis and X‐ray Crystallographic Structure of 2‐Pyridone Derivatives

A series of 3‐cyano‐2‐pyridone derivatives were synthesized by one‐pot four‐component condensation reaction involving a benzaldehyde derivative, alkyl cyanoacetate, acyclic or cyclic ketones, and ammonium acetate in reflux condition. The X‐ray structure of the products 5a and 5d confirm symmetric dimers via hydrogen bonding interactions between individual pyridine molecules showing, in addition, also π–π stacking interactions.     

“Grafting through” approach for synthesis of polystyrene/silica aerogel nanocomposites by in situ reversible addition-fragmentation chain transfer polymerization

Aerogel/polystyrene nanocomposites with mixed free and aerogel-attached polystyrene chains were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. 3-methacryloxypropyldimethylchlorosilane containing a double bond, which could be incorporated into polystyrene chains by a “grafting through” approach, was used as an aerogel modifier. Kinetics of RAFT polymerization of styrene in the presence of modified silica aerogel was studied by monitoring conversion and molar mass values. To further study, attached polymers were detached and their molecular characteristics were compared to free chains. According to results, the presence of silica aerogel particles has a sensible influence on polymerization kinetic and more aerogels result in decreased polymerization rate and conversion. The dispersity (Ð) of polymer chains increased by the addition of silica aerogel. In the case of aerogel-attached polystyrene chains, number-averaged molar mass values were slightly lower than that of free chains. Also, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques were used to observe the effect of loading on thermal properties of synthesized nanocomposites.     

Theoretical investigation of adsorption of the gabapentin drug on the heteroborospherene

Structural Chemistry - This is an analysis report on the use of density functional theory (DFT) to investigate the potentials of pristine and amino acid–functionalized C4B32 borospherenes in...     

CuI-catalyzed tandem synthesis of thioethers using aryl halides,electron-deficient alkenes,and sodium iso-propyl xanthogenate

A ligand-free, CuI-catalyzed protocol was developed for the one-step preparation of Michael adducts of aromatic thiols in high yields by reacting a mixture of an aryl halide and an electron-deficient alkene with sodium iso-propyl xanthogenate.     

Poly(styrene-co-butyl acrylate)/mesoporous diatomaceous earth mineral nanocomposites by in situ AGET ATRP

Journal of Thermal Analysis and Calorimetry - Mesoporous diatomite platelets were used for in situ copolymerization of styrene and butyl acrylate by activators generated by electron transfer for...     

Theoretical Modelling and Facile Synthesis of a Highly Active Boron‐Doped Palladium Catalyst for the Oxygen Reduction Reaction

A highly active alternative to Pt electrocatalysts for the oxygen reduction reaction (ORR), which is the cathode‐electrode reaction of fuel cells, is sought for higher fuel‐cell performance. Our theoretical modelling reveals that B‐doped Pd (Pd‐B) weakens the absorption of ORR intermediates with nearly optimal binding energy by lowering the barrier associated with O₂ dissociation, suggesting Pd‐B should be highly active for ORR. In fact, Pd‐B, facile synthesized by an electroless deposition process, exhibits 2.2 times and 8.8 times higher specific activity and 14 times and 35 times less costly than commercial pure Pd and Pt catalysts, respectively. Another computational result is that the surface core level of Pd is negatively shifted by B doping, as confirmed by XPS, and implies that filling the density of states related to the anti‐bonding of oxygen to Pd surfaces with excess electrons from B doping, weakens the O bonding to Pd and boosts the catalytic activity.     

Volumetric Properties of Tetra-n-butyl ammonium bromide in Aqueous Solutions of Magnesium sulphate in the Temperature Range 298.15 to 318.15K and under the Atmospheric Pressure

Density and sound speed measurements have been carried out for the ternary systems consisting of tetra-n-butyl ammonium bromide (TBAB) in 0.1 m aqueous magnesium sulphate heptahydrate (MgSO₄.7H₂O)-water over the full range of composition from T = 293.15 to 318.15 K by using volumetric method. Using this experimental data, various physical and thermodynamical parameters such as adiabatic compressibility, apparent molal compressibility, apparent molal volume, apparent and limiting partial molar volumes of the electrolytes and ions in these mixtures have been evaluated and split into respective ionic contributions. The results have been discussed in terms of ion–ion and ion–solvent interactions occurring between TBAB and aqueous MgSO₄ solutions. Further, structure making/breaking behaviour of MgSO4 has been reported in terms of sign of the partial molar expansibility at infinite dilution.     

Synthesis of calcium alginate nanoparticles for removal of lead ions from aqueous solutions

Calcium alginate nanoparticles (CANPs) were synthesized to remove lead ion [Pb(??)] as pollutant of environment from aqueous solutions. The produced CANPs were characterized by Fourier transform infrared spectroscopy (FTIR), particle size analysis (PSA) and scanning electron microscope (SEM). Various factors, which affected adsorption efficiency of lead ions by CANPs, such as pH (pH from 1 to 8), initial ions concentration (in the range of 25 to 125 mg L^–1), contact time (varying from 5 to 120 min), and adsorbent dose (50 to 500 mg L^–1), were investigated for determination of optimum experimental conditions. The result of tests showed that the investigated factors had significant effects on adsorption of Pb(??) ions and the maximum adsorption percentage of lead at pH = 6~7, 25 mg L^–1 initial ions concentration, contact time of more than 140 min. and for adsorbent dose at 500 mg L^–1. Also these results demonstrated the effective adsorption of Pb²⁺ ions by synthesized CANPs that occurred due to a high surface area of CANPs and the presence of anionic carboxylate functional groups and allowed effective absorbing and removing Pb(??) ions from aqueous solutions. Thus, these nanoparticles were able to remove over 99% of lead ions from solution.