Catalytic reduction of 4-nitrophenol by means of nanostructured polymeric Schiff base complexes

Polymeric Schiff base ligands were synthesized using 2-hydroxybenzaldehyde (L²), 4-hydroxy-3-methoxybenzaldehyde (L⁴), and 5-aminoisophthalic acid. The nanostructured complexes were then synthesized using Ni²⁺, Cu²⁺, and Mn³⁺. The ligands and complexes thus synthesized were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy. The thermal stability of the complexes was confirmed using TGA. The synthesized complexes were used as catalysts in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol in an aqueous phase in the presence of sodium borohydride. In this work, the catalytic reactivity of nanostructured complexes was compared using the rate constant (k) of the reaction. The reaction time for the reduction of 4-NP was 5–14 min for different complexes. The catalytic system based on Ni²⁺/2-hydroxybenzaldehyde was the most active and displayed reusability in the reduction of 4-NP.     

Synthesis and NMR spectroscopy of 1,3,3,5,5-pentaalkoxy-1-chlorocyclotriphosphazenes

A series of pentaalkoxychlorocyclotriphosphazenes was synthesized. The spectral characteristics of the synthesized compounds (³¹Р, ¹H, ¹³С NMR) were studied. It was shown that the complexity of the NMR spectra of pentaalkoxychlorocyclotriphosphazenes is associated with the magnetic nonequivalence of the phosphorus atoms in the triphosphazene cycle and the hydrogen and carbon atoms in the alkoxy groups on these phosphorus atoms, as well as the cis/trans isomerism of the latter groups.     

Analogs of purine nucleosides. 4. 7-Alkylated 9-(2-hydeoxymethyl)guanine

7,9-Disubstituted guaninium hydrohalides were synthesized by the reaction of 9- and 7-(2-hydroxymethyl)guanines with alkyl halides. The effect of the structure of the alkylating agent on the direction and yield of the alkylation reaction was established. The possibility of the conversion of the salts obtained to the free bases in a weakly alkaline medium was investigated. The synthesized compounds were characterized by the UV and ¹H and ¹³C NMR spectra. The ability of the synthesized compounds to inhibit replication of the herpes virus (VPG-1) was demonstrated.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 641–646, May, 1989.     

Study of fractal characteristics and rheological properties of Karbodon combined sorbent and its constituents

The structure-sorption properties of the bottom sediments and their compositions with the KAU carbon modified with K⁺, Mg²⁺, and Zn²⁺ cations, which were synthesized for the first time, were studied. The adsorption data were used to calculate the surface fractal dimension for composites under study and their constituents. The rheological curves of the composites synthesized in a wide range of the shear rates were obtained. The effect of their composition on the structure-mechanical properties (viscosity) of the sorbents was determined.     

Synthesis and characterization of new polyhydrazides based on 2,5-bis(mercapto-acetichydrazide)-1,3,4-thiadiazole moiety

New interesting class of novel polyhydrazides containing 1,3,4-thiadiazole moieties in the main chain was synthesized. A solution polycondensation technique was used in the synthesis of these polymers. The new monomer namely: 2,5-bis(mercapto-acetichydrazide)-1,3,4-thiadiazole III was synthesized from the nucleophilic replacement of 2,5-dimercapto-1,3,5-thiadiazole I with ethylchloroacetate, followed by hydrazinolysis. The model compound VII was synthesized from the monomer 2,5-bis(mercapto-acetichydrazide)-1,3,4-thiadiazole III with benzoyl chloride and characterized by ¹H- NMR, IR, and elemental analyses. The polyhydrazides were synthesized from the polymerization of monomer III with 4,4^′-biphenic, 3,3^′-azodibenzoyl, 4,4^′-azodibenzoyl dichlorides. These polymers were characterized by elemental and spectral analyses, viscometry and solubility. The thermal properties of these polymers were determined by thermal gravimetric analyses, and differential thermal analysis, and correlated with their structure. The crystallinity of some polymers was tested by X-ray analyses.     

The possibility of manganese disorder in LiMnPO4 and its effect on the electrochemical activity

Orthorhombic structured LiMnPO₄ was synthesized by a hydrothermal method. The possibility of manganese disorder in LiMnPO₄ was studied using powder X-ray diffraction and X-ray absorption fine structure analysis. A manganese-rich model was proposed for the hydrothermally synthesized LiMnPO₄. It is found that the extent of Mn²⁺ disorder on the Li⁺ sites was suppressed by increasing the reaction temperature, which led to an enhanced electrochemical activity. These observations are explained on the basis of the manganese-rich model, in which the disordered Mn²⁺ on the Li⁺ sites may act as a blockage in one-dimensional lithium ion transport pathway, thus reducing the electrochemical activity of the LiMnPO₄ prepared at low temperatures.     

Syntheses,structural characterizations,and thermal resistances of new epoxy–imide polymers

A new type of imide–epoxy resin in which imide compounds were grafted on the main chain of the epoxy was synthesized. The imide compounds used were mono (aminophthalimide)s. The structures of imide monomers and imide–epoxy polymers were confirmed by spectra characterizations of IR, ¹H-, and ¹³C-NMR. The thermal resistances and solubilities of synthesized imide–epoxy were also studied. © 1993 John Wiley & Sons, Inc.     

Synthesis of C14-labeled toluene

Summary C¹⁴-labeled toluene was synthesized by the alkylation of bromobenzene with methyl-C¹⁴ iodide. The yield of toluene-C¹⁴ was 80% on the original amount of methyl-C¹⁴ iodide and 87% on the amount that reacted.     

Synthesis of acyclic and macrocyclic analogs of Di-, Tri-, and tetranucleotides

Compounds consisting of two or three uracil fragments were synthesized by reaction of methyl-substituted uracil sodium salts with 1-(6-bromohexyl)-3,6-dimethyluracil or 1,6-dibromohexane. Treatment of these compounds with paraformaldehyde gave the corresponding pyrimidinophanes and acyclic compounds in which the uracil fragments are linked through methylene bridges. Uracil derivatives having no substituent on N³ were synthesized by reactions of silylated uracils with 1,3-bis(6-bromohexyl)uracil or 4,4′-(6-bromohexyloxy)diphenylmethane. The acyclic compound was converted into pyrimidinophane containing uracil fragments with N³H groups. A trinucleotide analog including uracil and two adenine fragments was synthesized from 1,3-bis(6-bromohexyl)uracil.     

Effect of polyvinylpyrrolidone as capping agent on Ce3+ doped flowerlike ZnS nanostructure

Nanoparticles of zinc sulfide doped with Ce³⁺ have been synthesized through a simple chemical precipitation method utilizing optimum dopant concentration (1.5 g) and employing various concentrations of polyvinylpyrrolidone (PVP, M.W: 40,000) as capping agent. The optical properties of the synthesized products were studied by UV–Vis absorption and photoluminescence measurements. The phase and size of the products were predicted by X-ray diffraction data. The existence of functional groups in the synthesized products was identified by Fourier transform infrared spectroscopy. Field emission scanning electron microscope results of Ce³⁺ doped ZnS show a uniform growth pattern of the nanorods with flowerlike structure. However, on surfactant assisted Ce³⁺ doped ZnS nanoparticles, the morphology of the products was changed from rod to spherical particles. The morphologies of the uncapped and PVP capped ZnS nanocrystals were confirmed by high resolution transmission electron microscopy.     

Synthesis,characterization, and in vitro toxicity evaluation of upconversion luminescence NaLuF4:Yb3+/Tm3+ nanoparticles suitable for medical applications

Synthesis, characterization, and in vitro toxicity evaluation of upconversion luminescence NaLuF₄:Yb³⁺/Tm³⁺ nanoparticles (UCLNPs) are reported in the current study. Initially, the synthesized lanthanide trifluoroacetate (Ln(OOCCF₃)₃) precursor was used to fabricate NaLuF₄ nanoparticles doped with Yb³⁺ and Tm³⁺ metal ions. The nanoparticles were coated with calcium carbonate (CaCO₃) after removing the hydrophobic species on them to enhance their biocompatibility. The in vitro methylthiazolyldiphenyl-tetrazoliumbromide (MTT) test was used to evaluate the toxicity of synthesized NaLuF₄:Yb³⁺/Tm³⁺ nanoparticles (NLF-5) on L929 mouse fibroblast cell lines. The transmission electron microscopy image showed that the particle size of NaLuF₄:Yb³⁺/Tm³⁺ was 32 nm. The synthesized NLF-5 nanoparticles have both α-cubic and β-hexagonal crystalline structures that provided a superb near-infrared-to-near-infrared upconversion luminescence signal when excited at 980 nm. MTT test results show that the death of L929 fibroblast cells was observed only at concentrations above 250 μg/mL of NaLuF₄:Yb³⁺/Tm³⁺ nanoparticles. In addition, with an increase in patrol time of 24, 48, and 72 hr, cell toxicity increased significantly, while the coated nanoparticles did not have any toxic effects. The synthesized nanoparticles could be used as a suitable material for medical applications due to their small particle size, high photoluminescence emission intensity, and low toxicity.     

Supercapacitor performance of activated carbon derived from rotten carrot in aqueous,organic and ionic liquid based electrolytes

In this work, we report the synthesis of porous activated carbon (AC). AC was derived from rotten carrot, at different values of activating temperature under inert atmosphere, employing chemical activation method and ZnCl₂ as activation agent. On the basis of results observed by surface area and pore size analysis, effect of activation temperature on synthesized AC was determined. Other material properties such as morphology, thermal stability, vibrational response, and crystal structure of prepared AC were studied using standard techniques of material characterization. Further, the electrochemical performance of synthesized AC was studied as an electrode, in aqueous, organic and ionic liquid based electrolyte. It was found that the synthesized AC based electrode exhibits highest specific capacitance (135.5?F?g^?1 at 10?mHz) in aqueous electrolyte and highest specific energy (29.1?Wh?kg^?1 at 2.2?A?g^?1) and specific power (142.5?kW?kg^?1 at 2.2?A?g^?1) in ionic liquid based electrolyte. This shows the suitability of synthesized material for use in energy storage applications.     

Effect of temperature on the sorption behavior of sodium potassium fluorophlogopite with respect to the heavy metal ions Cd<Superscript>2+</Superscript>, Hg<Superscript>2+</Superscript>, and Pb<Superscript>2+</Superscript>

The effect of temperature on the sorption behavior of a synthesized gel structurally close to the fluorine mica mineral, sodium potassium fluorophologopite, was studied for the heavy metal ions Cd²⁺, Hg²⁺, and Pb²⁺. The synthesized gel was characterized by X-ray powder pattern, energy dispersive spectrometry, infrared spectroscopy, and thermogravimetric analysis and was found to have the composition Na_0.5K_0.5Mg(AlSi₃O₁₀)F₂·6H₂O. The effect of temperature on sorption was studied with respect to varying concentrations of metal ions. The overall sorption capacity of the synthesized gel was found to depend on the number of ion active groups per unit weight of the material. The data were expressed in terms of distribution coefficients (K _d). Sorption data followed Freundlich adsorption isotherms. Studies showed that sorption decreased as the concentration of metal ions increased and increased as the temperature grew, which was evidence that the process was endothermic. The text was submitted by the authors in English.     

Carbon nanostructures as hydrogen sorbent for anode of a chemical power cell

Carbon nanofibers with a porous structure and a specific surface area of 300– 475 m² g¹ were synthesized by pyrolysis of acetylene on iron-containing catalysts. The possibility of using the carbon nanostructures synthesized as hydrogen sorbents to replace hydride-forming metal alloys in chemical power cells was analyzed.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 12, 2004, pp. 1980–1984.Original Russian Text Copyright © 2004 by Danilov, Melezhik.     

Synthesis of some 4-arylazo-3-hydroxythiophene disperse dyes for dyeing polyester fabrics

A series of novel 4-arylazo-3-hydroxythiophene disperse dyes was synthesized by heterocyclization of ethyl 2-arylhydrazono-2-phenylthiocarbamoyl acetates with a variety of α-halogenated reagents. The structures of the synthesized dyes were confirmed by UV-Vis, IR, ¹H NMR, and MS spectroscopic techniques and elemental analysis. The dyes were applied to conventional polyester fabric by high temperature exhaust dyeing. These dyes were found to give orange to reddish-violet shades with very good depth, levelness, and brightness on polyester fabric. The dyed fabric showed moderate to good light fastness and very good fastness to washing and perspiration. Also the position of color in CIELAB coordinates (L^*, a^*, b^*, H^*, and C^*) was assessed.     

Substituted 5-Antipyrinylazo-4-phenyl-2-aminothiazoles as Disperse Dyes for Dyeing Polyester Fabrics

Summary. A series of some new substituted 5-antipyrinylazo-4-phenyl-2-aminothiazole disperse dyes was synthesized by diazocoupling of 4-antipyrinyldiazonium chloride with aminothiazole derivatives. The synthesized dyes were characterized by UV-Vis absorption, IR, ¹H NMR, and MS spectroscopy. The dyes gave orange to reddish-violet shades with very good depth and levelness when applied to polyester fabrics as disperse dyes and their fastness properties were evaluated on polyester fibers. Also the position of color in CIELAB coordinates (L^*, a^*, b^*, H^*, and C^*) was assessed.     

Substituted 5-Antipyrinylazo-4-phenyl-2-aminothiazoles as Disperse Dyes for Dyeing Polyester Fabrics

A series of some new substituted 5-antipyrinylazo-4-phenyl-2-aminothiazole disperse dyes was synthesized by diazocoupling of 4-antipyrinyldiazonium chloride with aminothiazole derivatives. The synthesized dyes were characterized by UV-Vis absorption, IR, ¹H NMR, and MS spectroscopy. The dyes gave orange to reddish-violet shades with very good depth and levelness when applied to polyester fabrics as disperse dyes and their fastness properties were evaluated on polyester fibers. Also the position of color in CIELAB coordinates (L^*, a^*, b^*, H^*, and C^*) was assessed.     

Preparation of lithium fast ionic conductor by sol-gel-hydrothermal method

The solid fast ionic conductor was synthesized by the sol-gel-hydrothermal method. The influences of the dispersion reagent, the alkalinity and the calcination temperature on the surface morphology of nanopowders, and the electric conductivity were discussed. When PEG 12000 was used as the dispersion reagent, the alkalinity was 1.0% and the calcination temperature was 550°C; the electric conductivity at ambience temperature of the inorganic nanopowder of lithium fast ionic conductor synthesized was 2.59 × 10⁻³ S·cm⁻¹. __________ Translated from Journal of National University of Defense Technology, 2005, 27(2) (in Chinese)     

Synthesis,Characterization, and Pharmacological Evaluation of Some New Pteridine‐Based Heterocycles as Antimicrobial Agents

Considering pteridine as a worthy structure for improving probes of magnificent therapeutic potentials, some new pteridine conjugates were synthesized by aminomethylation of benzopteridinethione with a variety of primary aromatic amines and formaldehyde solution (37%) through the Mannich reaction. The proposed mechanism of formation of the synthesized compounds was discussed, and the structure of the newly synthesized compounds was elucidated on the basis of their IR, ¹H NMR, ¹³C NMR, mass spectral, and elemental analyses. Furthermore, some selected compounds were evaluated in vitro for their antimicrobial activities; the preliminary data stated that the majority of the tested compounds exhibited significant antimicrobial activity. Analogues 22 , 23 , 20 , 19 , 24 , and 15 were found to be the most potent against all the tested microorganisms.     

Synthesis of Surfactants from Alkali Lignin for Enhanced Oil Recovery

With the cheap and abundant resource of alkali lignin as feedstock, surfactants for enhanced oil recovery were synthesized by amination and alkylation reaction of lignosulfonate. The effects of amination conditions, including the ratio of raw materials, amination reagent, temperature, and reaction time, on nitrogen contents and surface tension of the surfactants were investigated. The results showed that ethylenediamine was more suitable for amination, and the molar ratio of alkali lignin, ethylenediamine, and formaldehyde was 1:2:1.5 at 80°C for 5 hours. The structure of synthesized products was characterized by Fourier transform infrared spectrometry. The HLB value of synthesized product was 10. The interfacial tension between Daqing crude oil and synthetic water could be decreased to 10^?2 mN/m with synthesized surfactant and NaOH at 45°C. Moreover, the effects of molecular weight of surfactants on interfacial tension were also studied. The synthesized surfactant (M_w > 10,000) showed a better interfacial activity on Daqing crude oil.