Copper(II) complexes with ligands derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one: synthesis and biological activity

The synthesis of Cu(II) complexes derived from Schiff base ligands obtained by the condensation of 2-hydroxybenzaldehyde or terephtalic aldehyde with 4-amino-antipyrine (4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one) is presented. The newly prepared compounds were characterized by( 1)H-NMR, UV-VIS, IR and ESR spectroscopy. The determination of the antimicrobial activity of the ligands and of the complexes was carried out on samples of Escherichia coli, Klebsiella pneumoniae, Acinetobacter boumanii, Pseudomonas aeruginosa, Staphylococcus aureus and Candida sp. The qualitative and quantitative antimicrobial activity test results proved that all the prepared complexes are very active, especially against samples of Ps. aeruginosa, A. Boumanii, E. coli and S. aureus.     

Gold metal-catalyzed reactions of isocyanides with primary amines and oxygen: analogies with reactions of isocyanides in transition metal complexes

Despite its generally poor catalytic properties, bulk gold metal is observed to catalyze reactions of isocyanides (CN-R) with primary amines (H2N-R') and O2 to give carbodiimides (R-N=C=N-R') at room temperature and above. Detailed infrared reflection absorption spectroscopic (IRRAS) and kinetic studies show that the reaction occurs by initial eta1-adsorption of the isocyanide on the Au surface, which activates the isocyanide to attack by the amine. This attack is the rate-determining step in the catalytic cycle and has characteristics very similar to those of amine reactions with coordinated isocyanides in transition metal complexes. However, the metallic Au surface provides a pathway involving O2 to give the carbodiimide product whereas homogeneous metal ion catalysts give formamidines [HC(=NR)(NHR')].     

Angular and local spectroscopic analysis to probe the vertical alignment of N-doped well-separated carbon nanotubes

Vertically aligned well-separated N-doped multiwalled carbon nanotubes (CNTs) were grown on a silicon substrate by plasma enhanced chemical vapor deposition (PECVD). Angular near-edge X-ray absorption fine structure (NEXAFS) was used to investigate the vertical alignment of as-grown CNTs. In addition, both individual tubes and tube bundles were characterized by high-resolution electron energy loss spectroscopy (HREELS). Simultaneous analysis of both spectroscopic techniques provides information on chemical environment, orbital orientation between carbon and heteroatoms, and local curvature effects. We demonstrate the utility of NEXAFS as an in situ probe of CNTs.     

d‐Secoestrone derivatives. V

The two title 16,17‐secoestrone derivatives, 3‐methoxy‐17‐oxo‐17‐phenyl‐16,17‐secoestra‐1,3,5(10)‐triene‐16‐nitrile, C₂₅H₂₇NO₂, (I) (17‐oxo substituent), and 17‐hydroxy‐3‐methoxy‐17‐phenyl‐16,17‐secoestra‐1,3,5(10)‐triene‐16‐nitrile, C₂₅H₂₉NO₂, (II) (17‐hydroxy substituent), have quite different conformations in the solid state. These conformational differences can be minimized by molecular mechanics calculations. Thus, the remarkable difference in the biological activity of the two compounds, e.g. the strong oestrogenic characteristics of (I) and the moderate antioestrogenic action of (II), must be caused by the difference in substitution at C17. In (II), the mol­ecules are linked by O—H?N hydrogen bonds, forming spirals along the b direction.     

Antisymmetry and stability of water systems. I. Planar cyclic clusters

All topologically distinct configurations of planar cyclic water clusters consisting of three to six molecules are calculated. The symmetry of configurations is analyzed using an additional operation of antisymmetry that changes the directions of all hydrogen bonds. It is concluded that the concept of antisymmetry and the presence of similar in properties but inequivalent “configurations-antipodes” reflects a new fundamental feature of water systems, namely, the internal molecular asymmetry.     

Novel microfabricated device for electrokinetically induced pressure flow and electrospray ionization mass spectrometry

A novel microchip device for electrospray ionization has been fabricated and interfaced to a time-of-flight mass spectrometer. Fluid is electrokinetically transported through the chip to a fine fused-silica capillary inserted directly into a channel at the edge of the device. Electrospray is established at the tip of the capillary, which assures a stable, efficient spray. The electric potential necessary for electrospray generation and the voltage drop for electroosmotic pumping are supplied through an electrically permeable glass membrane contacting the fluidic channel holding the capillary. The membrane is fabricated on the microchip using standard photolithographic and wet chemical etching techniques. Performance relative to other microchip electrospray sources has been evaluated and the device tested for potential use as a platform for on-line electrophoretic detection. Sensitivity was found to be approximately three orders of magnitude better than spraying from the flat edge of the chip. The effect of the capillary on electroosmotic flow was examined both experimentally and theoretically.     

Synthesis and properties of charge-transfer complexes based on quaternary salts of amines and tetracyanoquinodimethane

The electrical and optical properties of four charge-transfer complexes based on a molecule of tetracyanoquinodimethane (an acceptor) and donor molecules of quaternary salts of amines have been studied. It has been shown that the conductivity of the complexes has a semiconductor character and is determined by conduction along stacks of tetracyanoquinodimethane molecules.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 1, pp. 102–105, January–February, 1986.     

Anionic fullerenes, calixarenes, coronenes, and pyrenes as activators of oligo/polyarginines in model membranes and live cells

We report that the efflux of 5(6)-carboxyfluorescein anions from neutral egg yolk phosphatidylcholine vesicles is mediated by oligo/polyarginines only in the presence of activating amphiphilic anions. Screening of anion activators reveals best synergism for amphiphilic carboxylates (fullerene > calix[4]arene approximately coronene > pyrene > calix[6]arene > alkyl), whereas amphiphilic sulfates show less satisfactory activation despite often lower effective concentrations. The analogous alcohols and one calix[4]arene diphosphate were inactive. These results are discussed in the context of a tentative anion carrier mechanism, where interactions with bilayer (interface-directed translocation) and carrier (arene-templated carboxylate-guanidinium pairing) contribute to activator efficiencies. Applied to HeLa cells, pyrenebutyrate is shown to significantly increase the uptake of a fluorescently labeled octaarginine in a concentration-dependent manner.     

A note on normal bases of ideals in sextic algebraic number field

Let K/Q be a cyclic tamely ramified extension of degree 6, then any ambiguous ideal of K has a normal basis. Supported by grants GACR 201/07/0191, VEGA 2/4138/04, VEGA 1/0084/08.