Coordination compounds of copper and nickel with N,N′-[4,4′-(perfluoro-1,4-phenylene)bis(oxy)bis(4,1-phenylene)]-bis[2-(pyridin-2-ylmethylidene)hydrazinecarbothioamide] and its derivatives

N,N′-[4,4′-(Perfluoro-1,4-phenylene)bis(oxy)bis(4,1-phenylene)]bis[2-(pyridin-2-ylmethylidene)-hydrazinecarbothioamide] as well as its methyl and phenyl derivatives react with copper and nickel chlorides in ethanol to form coordination compounds. In the products, the hydrazinecarbothioamides act as doubly deprotonated bridging ligands. The prepared complexes have been found to inhibit in vitro the growth and propagation of the myeloid human leukemia HL-60 cancer cells at the 10^?5–10^?7 mol/L concentration.     

Kinetics of thermoinitiated oligomerization of 3,3′-(2,4,6-triethyl-1,3-phenylene)bis(5-methyl-1,2,4-oxadiazole)

The crystal structure of 3,3′-(2,4,6-triethyl-1,3-phenylene)bis(5-methyl-1,2,4-oxadiazole), which models the cross-linking fragment of polynitriles by benzodinitrile oxides, was determined by X-ray diffraction analysis. The kinetic regularities of its thermoinitiated oligomerization were studied by isothermal calorimetry and spectrophotometry. The process proceeds with self-acceleration, and the Arrhenius dependences of the initial and maximum reaction rates were determined. The reaction accelaration is determined by an increase in the viscosity of the reaction medium. Possible mechanisms were proposed for oligomerization.     

Experimental and theoretical characterization of N,N′-bis(2,4-dihydroxybenzylidene)-1,2-diaminobenzene schiff base and its Cu(II) complex

A new Schiff base ligand N,N′-bis(2,4-dihydroxybenzylidene)-1,2-diaminobenzene [=H₂L] and its Cu(II) complex [Cu(L)] are synthesized and characterized by IR, UV-Vis, NMR, mass spectrometry and elemental analysis. Also, the computational prediction of optimized geometries, IR spectra and NMR chemical shifts is performed using the density functional theory (DFT) method. The DFT optimized geometry of the ligand is not planar, so the three benzene rings are located in separate planes. The phenolic protons are engaged in the intramolecular hydrogen-bonding interactions. In the optimized geometry of the square comlex, dianionic L^2? acts as a tetradentate ligand, which occupies four coordination positions in the N, N, O^?, O^? manner. The consistency between the calculated and experimental results confirms the validity of the optimized structures for the H₂L ligand and its Cu complex.     

Molecular and crystal structure of 4,5,4′,5′-tetrahydro-2,2′-(1,4-phenylene)bisoxazoline

4,5,4,5-Tetrahydro-2,2-(1,4-phenylene)bisoxazoline, which is one of the most promising stabilizers-consolidators of heterochain polymers, was studied by X-ray structural analysis.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2506–2507, October, 1996.     

Synthesis,characterization and properties of 3,3′-diethyl-1,1′-oxydiethylenedicarbonyl bis(thiourea)

In this paper, 3,3′-diethyl-1,1′-oxydiethylenedicarbonyl bis(thiourea) (DEOECTU), was synthesized by phase transfer catalysis and then characterized by UV, elemental analysis, infrared spectra, mass spectrum, ¹H NMR and TGA. DEOECTU properties, such as response to metal ions, adsorption on sulfide mineral surfaces, and hydrometallurgical performance as flotation collectors, were also investigated. The results indicated that DEOECTU reacted chemically with Cu²⁺ ions through its S and N atoms in the C(=S)–NH–C(=O) group to form a new chelate compound, but no reaction of DEOECTU with Zn²⁺, Pb²⁺, Fe³⁺ or Fe²⁺ ions was observed. The results of adsorption and flotation experiments demonstrated, that compared to pyrite, sphalerite and galena, DEOECTU exhibited a superior collecting power for chalcopyrite and might attach on chalcopyrite surface by chemisorption. The further theoretical analysis from Pearson’s HSAB view point briefly explained the experimental results of the selective response of DEOECTU to Cu²⁺ ions and chalcopyrite.     

3,3′-dihydroxy-4,4′-[1,2-cyclohexanediyl-bis(nitrilomethylidyne)]-bis-phenol schiff-base and its Mn(II) complex: Synthesis, experimental, and theoretical characterization

In this work, a 3,3′-dihydroxy-4,4′-[1,2-cyclohexanediyl-bis(nitrilomethylidyne)]-bis-phenol [=H₂L] Schiff-base ligand and its Mn(II) complex [Mn(L)(H₂O)₂] are newly synthesized and characterized by elemental analysis, IR and NMR spectroscopies. Also the geometry optimizations, assignment of the IR bands and NMR chemical shifts are computed using the density functional theory (DFT) method. The DFT optimized geometry of the ligand is not planar; each of the cyclohexane and two benzene rings are located in separate planes. The phenolic protons are engaged in the intramolecular-hydrogen-bonding interactions with azomethine nitrogen atoms. In the optimized geometry of the octahedral Mn²⁺ complex, the dianionic L^2? acts as a tetradentate ligand in the N, N, O^?, O^? manner, where the coordinating atoms occupy the four equatorial positions. The two axial positions are occupied by two H₂O ligands. The theoretical and experimental results are in good agreement, confirming the validity of the optimized geometries for the H₂L ligand and its Mn complex.     

Europium,terbium, and ytterbium 3-(3′-triethoxysilylpropyl)pentane-2,4-dionates. Synthesis and the formation of luminescent sol-gel films

3-(3′-Triethoxysilylpropyl)pentane-2,4-dione, (EtO)₃SiCH₂CH₂CH₂C[-C(O)CH₃]₂ (I), was synthesized from 3-allylpentane-2,4-dione, CH₂ = CH-CH₂-C[-C(O)CH₃]₂, and triethoxysilane, (EtO)₃SiH, in the presence of Speier’s catalyst. The silylation occurred mainly at the terminal C atom of the allyl group. The corresponding europium(III), terbium(III), and ytterbium(III) β-diketonates were synthesized from compound I and appropriate metal isopropoxides and used to obtain transparent sol-gel films containing Eu³⁺, Tb³⁺, and Yb³⁺ cations. The film formation was studied by IR spectroscopy. It was found that moisture causes not only the hydrolysis and condensation of triethoxysilyl groups but also the hydration of the cation of the rare-earth metal. When the terbium complex was excited at the wavelength of one of the two peaks (230 and 308 nm) in the excitation spectrum, the cation fluoresced intensely at 491, 547, 585, and 623 nm due to the transitions ⁵ D ₄ → ⁷ F ₆, ⁵ D ₄ → ⁷ F ₅, ⁵ D ₄ → ⁷ F ₄, and ⁵ D ₄ → ⁷ F ₃, respectively. All these bands were narrow, the band at 547 nm being most intense. No emission from the organosilicon matrix at 440 nm was observed. The emission spectra of Eu³⁺-containing films showed, along with the bands at 593, 618, 667, and 700 nm due to the emission from the cation (⁵ D ₀ → ⁷ F ₁, ⁵ D ₀ → ⁷ F ₂, ⁵ D ₀ → ⁷ F ₃, and ⁵ D ₀ → ⁷ F ₄ transitions, respectively), an intense band at 491 nm due to the emission from the matrix.     

Synthesis of 4,4′-bis(dichloroamino)- and 4,4′-bis(chloroamino)-3,3′-azofurazans,the first representatives of dichloroamino- and chloroaminofurazans

First representatives of dichloroamino- and chloroaminofurazans, viz., 4,4′-bis(dichloroamino)- and 4,4′-bis(chloroamino)-3,3′-azofurazans, were synthesized by the chlorination of 4,4′-diamino-3,3′-azofurazan with sodium hypochlorite in the CH₂Cl₂—H₂O mixture.     

Blends of a novel high-temperature poly(oxy-1,4′-diphenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene) with poly(ether imide): structure, interaction, and miscibility

 Polymer miscibility has been discovered in a blend system comprising poly(ether imide) (PEI) and a new poly(ether diphenyl ether ketone) (PEDEK). The miscibility of the PEDEK/PEI polymer system (quenched from the molten state) was investigated in this study using differential scanning calorimetry and Fourier transform (FT-IR) spectroscopy. A composition-dependent single glass-transition temperature (T _g) in the PEDEK/PEI blends over a full composition range was observed; the sharp transition width and the T _g–composition relationship both suggest that the scale of mixing is fine and uniform. Evidence based on observation of the cold-crystallization peak and suppression of the blend crystallinity and melting peak also indicated intimate intermolecular mixing. The FT-IR result yielded further evidence that the physical interactions leading to miscibility were weak, with no apparent specific interactions between the constituent polymers. Relationships between structures and interactions responsible for the miscibility in PEI and several ether-ketone-type polymers are briefly discussed. Received: 8 July 1999 Accepted in revised form: 21 October 1999     

Antimicrobial effects of bis(Δ2-2-imidazolinyl)-5,5′-dioxime and its mono- and tri-nuclear complexes

Bis(Δ²-2-imidazolinyl)-5,5′-dioxime (H₂L) and its nickel, cobalt, zinc, cadmium and mercury complexes have been prepared and tested in vitro against different microorganisms in order to assess their antimicrobial properties. We used Bacillus subtilis RSKK 244, Micrococcus flavus, Streptococcus faecalis RSKK 500, Staphylococcus aureus RSKK 490 from Gram-positive bacteria; Pseudomonas aeruginosa RSKK 356, Salmonella typhimurium RSKK 1017, Escherichia coli RSKK 550, Enterobacter aerogenes RSKK 720 from Gram-negative bacteria, Candida tropicalis RSKK 665 and Penicillium raciborskii IMI 40568. This revised version was published online in June 2006 with corrections to the Cover Date.     

N,N′-(1,2-phenylene)bis­(pyridine-2-carboxamide) and N,N′-(1,2-cyclohexanediyl)bis(pyridine-2-carbox­amide) toluene hemisolvate

The crystal structures of N,N′-(1,2-phenyl­ene)­bis­(pyridine-2-carbox­amide), C₁₈H₁₄N₄O₂, (I), and N,N′-(1,2-cyclo­hexane­diyl)­bis­(pyridine-2-carbox­amide) have been determined, the latter compound as the toluene hemisolvate, C₁₈H₂₀N₄O₂·0.5C₇H₈, (II). In (I), the benzene ring is nearly coplanar with one of the pyridine rings and forms a dihedral angle of 59.4 (1)° with the other. However, in (II), the dihedral angle of the two pyridine rings is 70.0 (1)°.     

Study of the solid phase extraction and spectrophotometric determination of nickel using 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione in environmental samples

A rapid, sensitive and selective method for the determination of nickel based on the rapid reaction of nickel(II) with 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Ni(II)–CPAHPD complex with C18 membrane disks has been developed. In the presence of pH 6.8 buffer solution and cetylpyridinium bromide (CPB) medium, CPAHPD reacts with nickel to form a red complex of a molar ratio of 1:1 (nickel to CPAHPD). This complex was enriched by solid phase extraction (SPE) with C18 membrane disks. An enrichment factor of 100 was obtained by elution of the complex from the disks with the minimal amount of isopentyl alcohol. The molar absorptivity and Sandell sensitivity of the complex was 3.11 × 10⁵ L mol^?1 cm^?1 and 0.0189 ng cm^?2, respectively at 549 nm in the measured solution. Beer's law was obeyed in the range of 0.01–0.37 μg mL^?1, while that obtained by Ringbom plot was in the range of 0.025–0.35 μg mL^?1. The detection and quantification limits were calculated and found to be 0.003 and 0.01 μg mL^?1. The proposed method was applied to the determination of nickel in water, food, biological and soil samples with good results.     

Synthesis and Crystal Structure of 3,3-Di(acetic ether)-2,4-pentanedione

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Poly[(3,3′-dimethyl-1,1′-biphenyl-4,4′-diyl)ethynediyl(2,5-dioctyl-1,4-phenylene)ethynediyl] and a related copolymer – new blue EL polymers

Electroluminescence (EL) properties of a new poly(aryleneethynylene) and a related copolymer were studied. They are poly[(3,3′-dimethyl-1,1′-biphenyl-4,4′-diyl)ethynediyl(2,5-dioctyl-1,4-phenylene)ethynediyl] (PPEBE) and related copolymer (PPEBE-co-mP) containing 20 mole % of 1,3-phenylene units. Both polymers are blue-light emitters; the former was found to perform better than the latter when the light-emitting diode (LED) device had the configuration of ITO/PEDOT/polymer/Li:Al. The device constructed with the former polymer exhibited the external quantum efficiency of 0.05 and the maximum brightness higher than 400 cd/m² with its EL spectrum showing maxima at λ = 445 and 472 nm. The performance of the device constructed with the copolymer was about one fifth of the device fabricated with the homopolymer.     

Synthesis of N,N′-Bis(arylsulfanyl)cyclohexa-2,5-diene-1,4-diimines and N,N′-(Cyclohexa-2,5-diene-1,4-diylidene)bis(arenesulfinamides)

Russian Journal of Organic Chemistry - Reactions of (chlorosulfanyl)benzenes with benzene-1,4-diamines afforded new N,N′-bis(arylsul­fanyl)cyclohexa-2,5-diene-1,4-diimines which were...     

Determination of manganese(VII) as 3,3′-Dianisole-4,4′-bis(3,5-diphenyltetrazolium chloride) complex and its application

A simple, rapid, selective and sensitive spectrophotometric method is described for the determination of trace amounts of manganese using Blue tetrazolium chloride as a chromogenic reagent. The method is based on the formation of ion-associate complex between manganese(VII) and the cation of ditetrazolium salt, having an absorption maximum at 255 nm. Beer’s law is obeyed in the range of 0.1–1.6 μg mL^?1. The molar absorptivity and Sandell’s sensitivity were found to be 4.97 × 10⁴ L mol^?1 cm^?1 and 1.11 × 10^?3 μg cm^?2, respectively. Limit of deterction is 6.86 ng mL^?1 Mn(VII) and limit of quantitation is 22.8 ng mL^?1 Mn(VII). Optimum reaction conditions were evaluated. The effect of interfering ions on the determination is described. The extraction, distribution and association constants, and the recovery factor have been calculated.