Synthesis,structure and capacitive properties of cobalt hydroxide films on stainless steel substrates

Cobalt (hydro)oxide films on AISI 304 stainless steel and sintered metal fibre filter Bekipor ST 20AL3 were prepared using electrochemical deposition from neutral cobalt acetate solutions under galvanostatic conditions. Deposited films were structurally characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. All electrochemical measurements were performed in aqueous NaOH solution. Capacitive behavior of different films was evaluated using cyclic voltammetry data. The highest specific capacitance (965 F g^?1) was reached when Bekipor ST 20AL3 mesh was used as a support for electroactive substance.      

Polymer conjugates with potential biological activity based on new derivatives of 2-mercaptobenzoxazole-synthesis and characterization

New potentially biologically active compounds derived from 2-mercapto-benzoxazole were synthesized and coupled on polymeric support of poly (maleic anhydride-alt-vinyl acetate) for the preparation of polymer-drug conjugates with controlled drug release. All compounds were characterized by elemental and spectroscopy (FT-IR, ¹H-NMR) analysis. The toxicological tests recommend the products for further laboratory screening.      

Salutaridine and its derivatives as thebaine-equivalents in the synthesis of aporphines

Here we report the transformation of tetracyclic morphinan salutaridine (1) into 2,3,10,11-tetrasubstituted (R)-aporphines. This method serves as another chemical proof of the previously verified biosynthetic connection with pentacyclic morphinan-6,8-diene-type thebaine. In the presence of nucleophiles, this procedure could lead to pharmacologically interesting new tetrasubstituted aporphinoids. The enantioselective synthesis of 7S-salutaridinol (2) has been also achieved in order to investigate the acid-catalyzed reactions of this natural morphinan.      

Metals content of soil,leaves and wild fruit from Serbia

The concentrations of Zn, Mn, Fe, Pb, Ni, Cu and Cd in soil, leaves and edible wild fruit (Crataegus laevigata L., Cornus mas L. and Prunus spinosa L.) from southeast Serbia were determined by atomic absorption spectroscopy. Metal translocations from soil to fruit were calculated as well as their oral intake and health risk indices. Positive correlations were found among metal concentrations in soil, leaves and fruit.      

Aerobic oxidation of cumene catalysed by 4-alkyloxycarbonyl-N-hydroxyphthalimide

4-Hexyloxycarbonyl-, 4-dodecyloxycarbonyl- and 4-hexadecyloxycarbonyl-N-hydroxyphthalimides were synthesised using trimellitic anhydride chloride as the starting material. The obtained lipophilic derivatives of N-hydroxyphthalimide were applied as catalysts of the cumene oxidation reaction with oxygen performed in polar acetonitrile, in non-polar tert-butylbenzene and in the absence of a solvent. The courses of reactions catalysed by N-hydroxyphthalimide and its derivatives were compared.      

In vitro biological activity comparison of some hydroxyapatite-based composite materials using simulated body fluid

Hydroxyapatite composites are the main biomaterials used for metal implant coatings. Their in vitro study is very important. That is why their behavior was monitored in simulated body fluid (SBF), which is a solution with ion concentrations and pH value similar to those of human blood plasma. Silica, chitosan and gelatin-doped hydroxyapatite-based biomaterials were studied in SBF; the samples were characterized pre-, during and post-SBF immersion using infra-red, scanning and transmission electron spectroscopy and X-ray diffraction methods. The solubility of materials in SBF was determined, and the variation of Ca²⁺ and phosphorus concentration was also recorded during SBF experiments. The results were compared and their in vitro biological activity was determined.      

P-Triazinylphosphonium chlorides as a new group of coupling reagents

Tertiary phosphines in reaction with 2-chloro-4,6-dialkoxy-1,3,5-triazines gave unstable quaternary P-triazinylphosphonium chlorides, which readily decomposed with a departure of the alkyl group of the triazine ring substituent. Stable quaternary P-triazinylphosphonium chlorides were obtained only in reaction of 2-chloro-4,6-diphenoxy-1,3,5-triazine. Both, stable quaternary P-triazinylphosphonium chlorides as well unstable analogues prepared in situ activated carboxylic acid yielding “superactive” triazine esters, useful as highly efficient reagents in peptide bond synthesis.      

Supramolecular complexes of podand ligands with xenon

Formation of stable complexes between xenon and podand polyoxyethylene ligands was ascertained. The complexation process was studied by ¹²⁹Xe NMR titration, NMR diffusiometry and heteronuclear NOE measurements. The ligands studied form a 1:1 complexes with Xe(0). Their stability constants depend on the ligand structure, i.e., polyoxyethylene chain length, number of complexating polyether units and the topology of the anchoring centre.      

Reaction of barbituric acid with organic azides and phosphonium ylides

Amination by organic azides has been carried out to provide aminobarbiturates by fusion of a triazole ring to the 5,6-positions of barbituric acid followed by cleavage and thermal elimination of nitrogen, whereas aza-Wittig reaction gave phosphoranylidene barbituric acid salts.      

The first synthesis of 3-deoxyoripavine and its utilization in the preparation of 10-deoxyaporphines and cyprodime

The synthesis of 3-deoxyoripavine (7) was realized as a novel and promising intermediate towards the synthesis of the important class of dopaminergic and/or serotonergic 10-deoxyaporphines and the special pharmacological tool µ opioid antagonist cyprodime. Generally, the preparation of these valuable biologically active compounds was achieved in remarkable yields.      

Preparation of selectively protected protoescigenin derivatives for synthesis of escin analogs and neoglycoconjugates

Protoescigenin, the main aglycone of horse chestnut saponin mixture known as escin, was selected as substrate for exploratory chemistry towards selective protection, followed by propargyl ether formation and subsequent condensation with azido-monosaccharides, to obtain novel triazole linked conjugates of the triterpene.      

Application of UV detection in HPLC in the total antioxidant potential assay

HPLC has been already used for the TAP estimation. Phenylalanine, salicylic, p-hydroxybenzoic (pHBA) or terephthalic (TPA) acids have been used as sensor compounds. Products of their reaction with the hydroxyl radicals, generated in the Fenton-like reaction, were analyzed using electrochemical or fluorescence detection. This paper describes the TAP assay based on the hydroxyl radicals reaction with pHBA, reversed-phase-HPLC separation and UV photometric detection. The elaborated assay has been used to evaluate TAP values of some apiculture products.      

Fabrication of superhydrophobic surface of stearic acid grafted zinc by using an aqueous plasma etching technique

A stable superhydrophobic surface of stearic acid grafted zinc was fabricated with two steps, that is, the zinc surface was firstly treated with glow discharge electrolysis plasma (GDEP) and then followed by a grafted reaction of stearic acid onto the treated zinc surface. Results indicated that the wettability of zinc substrate changed from superhydrophily to superhyphodrobicity with a water contact angle (CA) up to 158° and a water sliding angle (SA) less than 5°. The surface morphology and composition were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively.      

Volumetric and Viscometric Studies in Binary Liquid Mixtures of 2-Methyl-2-propanol with Some Ketones at Different Temperatures

Densities, ??, and viscosities, ??, of binary mixtures of 2-methyl-2-propanol with acetone (AC), ethyl methyl ketone (EMK) and acetophenone (AP), including those of the pure liquids, were measured over the entire composition range at 298.15, 303.15 and 308.15?K. From these experimental data, the excess molar volume $V_{\mathrm{m}}^{\mathrm{E}}$ , deviation in viscosity ????, partial and apparent molar volumes ( $\overline{V}_{\mathrm{m},1}^{\,\circ }$ , $\overline{V}_{\mathrm{m},2}^{\,\circ }$ , $\overline{V}_{\phi ,1}^{\,\circ}$ and $\overline{V}_{\phi,2}^{\,\circ} $ ), and their excess values ( $\overline{V}_{\mathrm{m},1}^{\,\circ \mathrm{E}}$ , $\overline{V}_{\mathrm{m,2}}^{\,\circ \mathrm{ E}}$ , $\overline {V}_{\phi \mathrm{,1}}^{\,\circ \mathrm{ E}}$ and $\overline{V}_{\phi \mathrm{,2}}^{\,\circ \mathrm{ E}}$ ) of the components at infinite dilution were calculated. The interaction between the component molecules follows the order of AP > AC > EMK.     

Organoruthenium(II) thiosemicarbazone complexes: synthesis, spectral characterization, DNA binding and DNA cleavage studies

A series of new ruthenium(II) complexes were synthesized with Schiff bases derived from salicylaldehyde / o-hydroxyacetophenone/ o-vanillin / 2-hydroxy-1-naphthaldehyde with thiosemicarbazide and acetyl furan. They are characterized by elemental analysis, IR, electronic, ¹H NMR, ¹³C NMR and mass spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Four of these complexes were tested for its binding with CT-DNA using absorption spectroscopic studies and two of these complexes exhibit efficient DNA cleavage activity.      

Quantification of sunscreen 2-phenylbenzimidazole-5-sulfonic acid in cosmetic products and water samples by HPTLC/densitometry with fluorescent detection

The water-soluble sunscreen 2-phenylbenzimidazole-5-sulfonic acid (PBS) was quantified in a sun-care product and water samples by thin layer chromatography followed by densitometric scanning in fluorescence mode (cut-off filter 370 nm, wavelength of excitation — 300 nm). Normal phase TLC was performed on silica gel 60 as stationary phase. Mobile phase used was ethyl acetate-ethanol-water 70:35:30 (v/v/v). The limit of detection (LOD) was 0.0004 μg spot-1, and the limit of quantification (LOQ) was — 0.001 μg spot^?1 without any sample pre-concentration.      

Effect of hydrothermal treatment on the structure of an aluminosilicate polymer

The effect of hydrothermal treatment on the structure of an aluminosilicate polymer prepared by a polycondensation reaction between silicate and hydroxoaluminate in alkaline aqueous solution was studied. The structural changes were investigated using X-ray diffraction analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy imaging and thermogravimetric analysis. The results indicated that the amorphous aluminosilicate polymer transformed into a crystalline product during the hydrothermal treatment at 145°C. The crystalline phase was identified as a mineral of the zeolite group, most likely phillipsite. This transformation required an alkaline environment during the hydrothermal treatment.      

Densities,Refractive Indices,Ultrasonic Speeds and Excess Properties of Acetonitrile + Poly(ethylene glycol) Binary Mixtures at Temperatures from 298.15 to 313.15 K

The densities, ρ, refractive indices, n _D, and ultrasonic speeds, u, of binary mixtures of acetonitrile (AN) with poly(ethylene glycol) 200 (PEG200), poly(ethylene glycol) 300 (PEG300) and poly(ethylene glycol) 400 (PEG400) were measured over the entire composition range at temperatures (298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure. From the experimental data, the excess molar volumes, \( V_{\text{m}}^{\text{E}} \) , deviations in refractive indices, \( \Delta n_{\text{D}} \) , excess molar isentropic compressibility, \( K_{{s , {\text{m}}}}^{\text{E}} \) , excess intermolecular free length, \( L_{\text{f}}^{\text{E}} \) , and excess acoustic impedance, Z ^E, have been evaluated. The partial molar volumes, \( \overline{V}_{\text{m,1}} \) and \( \overline{V}_{\text{m,2}} \) , partial molar isentropic compressibilities, \( \overline{K}_{{s , {\text{m,1}}}} \) and \( \overline{K}_{{s , {\text{m,2}}}} \) , and their excess values over whole composition range and at infinite dilution have also been calculated. The variations of these properties with composition and temperature are discussed in terms of intermolecular interactions in these mixtures. The results indicate the presence of specific interactions among the AN and PEG molecules, which follow the order PEG200 < PEG300 < PEG400.