Synthesis,characterization, and biological activity of Cd(II) and Mn(II) coordination polymers based on pyridine-2,6-dicarboxylic acid

The coordination polymers (CPs) {[Cd(Pydc)(H₂O)₃] · PydcH₂} (I) and [Mn(Pydc)(H₂O)₃] · PydcH2} (II) were obtained by the reaction of CdSO₄ · 5H₂O or MnCl₂ · 4H₂O with pyridine-2,6-dicarboxylic acid (PydcH₂). The structures of the CPs I and II were characterized by IR, UV-Vis, TGA, and X-ray single crystal analysis (CIF files CCDC nos. 1417757 (I), 1417758 (II)). The network structures of I and II are constructed by an infinite number of discrete binuclear molecules and free PydcH2. The structures of the CPs I and II connected by the extensive H-bonds and π–π stacking, forming a 3D-network. The CPs I and II were screened to test their antimicrobial activities against different species of bacteria and fungi.     

Shock compression of simple molecules

A simple approach is developed to calculate shock compression of simple molecules. This approach is based upon an accurate analytic representation of the Lennard-Jones fluids in conjunction with the Enskog theory, which is used to calculate the molecular diameter as a function of temperature along the Hugoniot. The model permits rapid, yet reliable calculations. It is applied to N₂, O₂, H₂, D₂, CH₄, CO, and CO₂. The results are tested by the comparison with experimental data and with other calculations. The computed Hugoniots agree reasonably with experimental results for many (but not all) simple molecules and are comparable to those of more complicated models.     

Innovative biotemplates for the synthesis of ZnO nanoparticles with versatile morphologies

Journal of Sol-Gel Science and Technology - ZnO nanoparticles with different morphologies were prepared via the biotemplate method. The microstructure of synthesized nanoparticles was found to...     

Development of surface treated nanosilica for wettability alteration and interfacial tension reduction

The present study examines and compares the effect of surface treatments of nano-silica using internal olefins sulphonates (IOS_20–24 and IOS_19–23), anionic surfactants. The effect of surface modification on colloidal stability, wettability alteration and oil-water interfacial tension reduction were analyzed. Silica nanoparticles were characterized using Field Emission Scanning Electron Microscope (FESEM) and integrated energy-dispersive X-ray spectroscopy (EDX) before and after surface treatment. Using Turbiscan classic, the optimal nanosilica concentration and inspection of the coated particles dispersion stability with the help of light transmission behavior through the nanofluid was carried out. The stability was found to be enhanced as the mean light transmission declined only after surfactant treatment in both IOS coated nano-silicas but IOS_19–23 O-342 coated dispersions proved to be more stable among all three. RAME-HART Goniometer was used to perform interfacial tension (IFT) and contact angle measurements. IFT was found to be reduced by 48% after the surfactant treatment in case of IOS_19–23 O-342 coated nanosilica. Both surface treatments of nanosilica and increasing silica concentration caused significant reduction and altering wettability towards more water wet. The results revealed that IOS coatings improved the efficiency of NPs dispersion in terms of altered wettability and reduced IFT that mimics their potential for EOR applications.     

Consequences of resonance tunnelling in chemical kinetics

The kinetic consequences of resonance tunnelling processes that may occur in chemical reactions are investigated in terms of a multi-centered unsymmetrical Eckart potential barrier. This potential function does not only simulate the possible existence of intermediate wells in the effective potential energy cut along the reaction path, but also is amenable to analytic solutions. The reaction rate as well as its dependence on temperature, reduced mass,Q-value, activation energy and barrier diffuseness are evaluated for successively increasing the number of barrier stages. Comparisons between results due to single and multi-humped potential energy barriers are made and discussed.