4-{[(1E)-(2-Hydroxyphenyl)methyl­idene]amino}-1,5-dimethyl-2-phenyl-2,3-dihydro-1H-pyrazol-3-one

In the title compound, C₁₈H₁₇N₃O₂, a strong intramolecular O—H⃛N hydrogen bond [N⃛O 2.607 (3), O—H 0.97 (3) and H⃛N 1.71 (3) Å, and O—H⃛N 153 (2)°] was observed, which leads to a unique phenol–imine tautomerism in the solid state. The C=N imine bond distance and the C—N—C bond angle [1.287 (2) Å and 121.7 (1)°, respectively] indicate the existence of this phenol–imine tautomer. In solution, the phenol–imine tautomer of the title free Schiff base ligand is dominant in both polar and non-polar solvents, as supported by ¹H NMR and UV–visible spectroscopic data.     

On the fine spectra of triangular Toeplitz operators

The fine spectra of triangular double-band and triple-band matrices were examined by several authors. Here we determine the fine spectra of Toeplitz operators, which are represented by upper and lower triangular n-band infinite matrices, over the sequence spaces c₀ and c. Also some spectral results over ?_∞ are given.     

Evaluation of vanillic acid as inhibitor of carbonic anhydrase isozyme III by using a modified Hummel–Dreyer method: approach for drug discovery

α‐3 carbonic anhydrase isozyme (CAIII) is the most abundant protein in adipocytes and considered insensitive to sulfonamide inhibitors. It was reported recently that the knock‐down of CAIII is attributed with controlling lipogenesis. Thus inhibition of this target may lead to the discovery of new therapies against obesity and insulin resistance. Vanillic acid as a small molecule with coordinating groups and has a potential to bind zinc atoms in CA binding sites. Inhibition of CAIII by vanillic acid was evaluated by Hummel–Dreyer chromatography because it provides free interaction between ligand and macromolecule and introduces solution for faulty results obtained by current colorimetric assays. HPLC system of vanillic acid produces vacancy (negative) peak representing the amount of attached vanillic acid with CAIII. It was found that vanillic acid is able to bind with CAIII through two equilibria, one at equimolar ratio and another at 2:1 (vanillic acid–CAIII) ratio. The affinity constant of equimolar binding between CAIII and vanillic acid was found to be 14,400 m ^?1. It was found that vanillic acid binding with CAIII is much stronger than phenol and acetazolamide (positive controls). Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of surface structure on the catalytic behavior of Ni：Cu/Al and Ni：Cu：K/Al catalysts for methane decomposition

Methane decomposition using nickel, copper, and aluminum （Ni：Cu/Al） and nickel, copper, potassium, and aluminum （Ni：Cu：K/Al） modified nano catalysts has been investigated for carbon fibers, hydrogen and hydrocarbon production. X-ray photoelectron spectroscopy （XPS）, static secondary ion mass spectrometry （SSIMS）, thermal gravimetric analysis （TGA）, Fourier transform infrared （FT-IR）, secondary electron microscopy/X-ray energy dispersive （SEM-EDX）, and temperature programmed desorption （TPD） were used to depict the chemistry of the catalytic results. These techniques revealed the changes in surface morphology and structure of Ni, Cu, Al, and K, and formation of bimetallic and trimetallic surface cationic sites with different cationic species, which resulted in the production of graphitic form of pure carbon on Ni：Cu/Al catalyst. The addition of K has a marked effect on the product selectivity and reactivity of the catalyst system. K addition restricts the formation of carbon on the surface and increases the production of hydrogen and C2, C3 hydrocarbons during the catalytic reaction whereas no hydrocarbons are produced on the sample without K. This study completely maps the modified surface structure and its relationship with the catalytic behavior of both systems. The process provides a flexible route for the production of carbon fibers and hydrogen on Ni：Cu/Al catalyst and hydrogen along with hydrocarbons on Ni：Cu：K/Al catalyst. The produced carbon fibers are imaged using a transmission electron microscope （TEM） for diameter size and wall structure determination. Hydrogen produced is COx free, which can be used directly in the fuel cell system. The effect of the addition of Cu and its transformation and interaction with Ni and K is responsible for the production of CO/CO2 free hydrogen, thus producing an environmental friendly clean energy.     

Synthesis and biological activity of ester- and amide-functionalized imidazolium salts and related water-soluble coinage metal N-heterocyclic carbene complexes

N-Heterocyclic carbene (NHC) ligand precursors, namely, HIm(A)Cl [1,3-bis(2-ethoxy-2-oxoethyl)-1H-imidazol-3-ium chloride] and HIm(B)Cl {1,3-bis[2-(diethylamino)-2-oxoethyl]-1H-imidazol-3-ium chloride}, functionalized with hydrophilic groups on the imidazole rings have been synthesized and were used in the synthesis of corresponding carbene complexes of silver(I) and copper(I), {[Im(A)]AgCl}, {[Im(A)]CuCl}, and {[Im(B)](2)Ag}Cl. Related Au(I)NHC complexes {[Im(A)]AuCl} and {[Im(B)]AuCl} have been obtained by transmetalation using the silver carbene precursor. These compounds were characterized by several spectroscopic techniques including NMR and mass spectroscopy. HIm(B)Cl and the gold(I) complexes {[Im(A)]AuCl} and {[Im(B)]AuCl} were also characterized by X-ray crystallography. The cytotoxic properties of the NHC complexes have been assessed in various human cancer cell lines, including cisplatin-sensitive and -resistant cells. The silver(I) complex {[Im(B)](2)Ag}Cl was found to be the most active, with IC(50) values about 2-fold lower than those achieved with cisplatin in C13*-resistant cells. Growth-inhibitory effects evaluated in human nontransformed cells revealed a preferential cytotoxicity of {[Im(B)](2)Ag}Cl versus neoplastic cells. Gold(I) and silver(I) carbene complexes were also evaluated for their ability to in vitro inhibit the enzyme thioredoxin reductase (TrxR). The results of this investigation showing that TrxR appeared markedly inhibited by both gold(I) and silver(I) derivatives at nanomolar concentrations clearly point out this selenoenzyme as a protein target for silver(I) in addition to gold(I) complexes.     

Physicochemical properties determined by ΔpKa for protic ionic liquids based on an organic super-strong base with various Brønsted acids

Neutralization of an organic super-strong base, 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU), with different Br?nsted acids affords a novel series of protic ionic liquids (PILs) with wide variations in the ΔpK(a) of the constituent amine and acids. The physicochemical properties of these PILs, such as thermal properties, density, conductivity, viscosity, self-diffusion coefficient, vibrational stretching frequency, and (1)H-chemical shifts of the N-H bond, have been studied in detail. The generated PILs have melting temperatures below 100 °C, and six are liquids at ambient temperatures. Thermogravimetric analyses (TGA) conducted under isothermal and programmed heating conditions have shown that PILs with ΔpK(a)≥ 15 exhibit good thermal stability similar to aprotic ionic liquids. For instance, PILs with ΔpK(a) > 20 show remarkably high short-term thermal stability up to ca. 450 °C under a nitrogen atmosphere. The viscosity, ionic conductivity, and molar conductivity of the PILs fit well with the Vogel-Fulcher-Tamman equation for their dependencies on temperature. The relative cationic and anionic self-diffusion coefficients of the PILs estimated by the pulsed-field gradient spin-echo (PGSE) NMR method appear to be dependent on the structure and strength of the Br?nsted acids. Evaluation of the ionicity based on both the Walden plot and PGSE-NMR revealed that it increases until ΔpK(a) becomes 15 for the PILs.     

The Effect of Biocompatible Coating Layers on Magnetic Properties of Superparamagnetic Iron Oxide Nanoparticles

The g-factor of the exteremely proton-rich nucleus ²³Al(T _{1 / 2} = 0.47 s) has been measured for the first time, applying β-NMR technique on this nucleus implanted in Si. The obtained ∣g∣ = (1.58 ± 0.2) suggests that the spin of the ground state of ²³Al is 5 / 2. The magnetic moment is determined as ∣μ∣ = (3.95 ± 0.55) μ _N .