Synthesis and Characterization of New Unsymmetrically Substituted Phthalocyanines

 Unsymmetric metallophthalocyanines (M=Zn, Co, Ni) carrying alkylthio and acetyloxyethylthio groups on peripheral positions were prepared from 4,5-bis-alkylthio-phthalonitrile, 4,5-bis-(acetyloxyethylthio)-phthalonitrile, and the corresponding anhydrous metal salts Zn(CH₃COO)₂, NiCl₂, and CoCl₂. The extremely soluble compounds were characterized by their IR, ¹H NMR, and UV/Vis spectra. Their long wavelength absorption band was found to be bathochromically shifted; their solubility is superior to that of symmetrical phthalocyanines.     

Synthesis and Complexation of a New vic -Dioxime Ligand

 A new vic-dioxime ligand, N,N′-bis-(8-salicylideneimino-1-naphthyl)-diaminoglyoxime, has been synthesized from anti-dichloroglyoxime and 1-amino-8-salicylideneiminonaphthalene which has been prepared via the condensation product of 1,8-diaminonaphthalene and salicylaldehyde. The vic-dioxime ligand forms trinuclear complexes with Cu(II), Ni(II), Co(II), and Pd(II). The uranyl complex of this ligand has a 2:1 metal-ligand ratio and a binuclear structure with μ-hydroxo bridges.     

The Effect of MoS x Nanocoatings on the Water Electrolysis Performance Using a Nickel-Foam-Based Bifunctional Catalyst

The ability to increase the efficiency of electrochemical H2 and O2 evolution reactions in an alkaline solution using nickel-foam-based electrodes has been studied. To improve the catalytic properties of the foam, it was subjected to complex modification via sulfurizing in sulfur-containing gaseous media and the additional formation of amorphous or crystalline MoSx nanolayers. The foam was sulfidized in hydrogen sulfide or sulfur vapor at a temperature of 400°C. Amorphous MoSx films were produced via pulsed laser deposition from a MoS2 target in an H2S atmosphere. To obtain nanocrystalline catalytic MoSx layers, thin-film Mo precursors were preliminarily applied to the foam pre-sulfurized in sulfur vapor at 400°C. The deposition of precursors was carried out in vacuum at 22°C. After deposition, the foam with precursors was oxidized in air at 600°C. The modified samples were probed via scanning electron microscopy involving microanalysis and Raman spectroscopy. The effect of the precursor layer thickness on the sulfurizing efficiency and phase composition of the modified layers was established. The amorphous layer deposition was found to have a strong impact on only the O2 evolution. The crystalline layers obtained via sulfidizing of Mo-containing precursors exerted influence on both the cathodic and anodic reactions. The hydrogen overvoltage at a current density of 10 mA/cm2 was −160 mV, and the oxygen overvoltage was below 150 mV, which corresponded to the best electrocatalysts on the nickel foam after the volume modification via conventional chemical treatment (hydro- and solvothermal synthesis).     

Synthesis of novel carboxamide- and carbohydrazide-benzimidazoles as selective butyrylcholinesterase inhibitors

Molecular Diversity - Selectively inhibiting butyrylcholinesterase (BChE) is hypothesized to help in the management of Alzheimer’s disease (AD). Several studies have determined a correlation...     

Substituents Effects to the Electrochemical,and In Situ Spectroelectrochemical Behavior of Metallophthalocyanines: Electrocatalytic Application for Hydrogen Evolution Reaction

This study describes the effects of the number of fluoro substituents to the electrochemical, in situ spectroelectrochemical, and electrocatalytic activities of metallophthalocyanines for the hydrogen evolution reaction. Tuning of the number of fluoro groups shifts the redox processes and affects the aggregation tendencies of the complexes. An in situ electrocolorimetric method was applied to investigate the color of the electrogenerated anionic and cationic forms of the complexes. Cobalt phthalocyanines incorporated into Nafion film on a glassy carbon electrode decreases the overpotential of the working electrode for H⁺ reduction. The number and position of the electron withdrawing substituents and nature of the metal center change the electrocatalytic activities for the hydrogen evolution reaction in aqueous solutions.     

Preparation of aluminum-doped zinc oxide (AZO) nano particles by hydrothermal synthesis

Aluminum doped zinc oxide (AZO) nanometric particles were synthesized by hydrothermal method. Aluminum nitrate hydrate, aluminum sec-butoxide and zinc nitrate hydrate were used as the starting materials, and n-propanol and 2-butanol were used as solvents. Ratio of Al₂O₃ in ZnO was kept at 10 wt%. Reaction was conducted in a Teflon autoclave at 175–225 °C for 5 h. Ratios of alcohol, H₂O and HCl to zinc nitrate hydrate were altered and 6 different sets of parameters were investigated. Obtained products were subjected to powder-XRD, particle size measurement, TEM examination and AAS analysis. Single phase AZO particles were obtained at alcohol to zinc nitrate ratio of 35, acid to zinc nitrate ratio of 0.2, at 225 °C. Particle size was determined as 3.2 ± 0.4 nm from TEM examinations and as 1–2 nm from dynamic light scattering. Synthesized particles have amphiphilic character, thus they can be dispersed in both polar and non-polar media. It was seen from the UV-diffuse reflectance spectra that the AZO powder had low reflectance in the UV region and high reflectance in the visible region. The obtained powder has the potential to be utilized in the form of thin films for optical and electronic purposes.     

Rheology of polydimethylsiloxane swollen with supercritical carbon dioxide

Viscosity curves were measured for polydimethyl siloxane (PDMS) melts swollen with dissolved carbon dioxide at 50 and 80°C for shear rates ranging from 40 to 2300 s⁻¹, and for carbon dioxide contents ranging from 0 to 21 wt %. The measurements were performed with a capillary extrusion rheometer modified for sealed, high-pressure operation to prevent degassing of the melt during extrusion. The concentration-dependent viscosity curves for these systems are self-similar in shape, exhibiting low-shear rate Newtonian plateau regions followed by shear-thinning “power-law” regions. Considerable reduction of viscosity is observed as the carbon dioxide content is increased. Classical viscoelastic scaling methods, employing a composition-dependent shift factor to scale both viscosity and shear rate, were used to reduce the viscosity data to a master curve at each temperature. The dependence of the shift factors on polymer chain density and free volume were investigated by comparing the shift factors for PDMS-CO₂ systems to those obtained by iso-free volume dilutions of high molecular weight PDMS. This comparison suggests that the free volume added to PDMS upon swelling with dissolved carbon dioxide is the predominant mechanism for viscosity reduction in those systems. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 523–534, 1997     

Equilibrium Fluctuations in Lysozyme and Myoglobin

Hyperfine Interactions - The angular dependencies of inelastic intensities of Rayleigh scattering of Mössbauer radiation were measured for lysozyme and myoglobin (for different degrees of...