Search results for "METALS"
showing 10 items of 2013 documents
Effect of primary mild stresses on resilience and resistance of the nitrate reducer community to a subsequent severe stress
2008
International audience; The factors regulating soil microbial stability (e.g. resistance and resilience) are poorly understood, even though microorganisms are essential for ecosystem functioning. In this study, we tested whether a functional microbial community subjected to different primary mild stresses was equally resistant or resilient to a subsequent severe stress. The nitrate reducers were selected as model community and analysed in terms of nitrate reduction rates and genetic structure by narG PCR-restriction fragment length polymorphism fingerprinting. Heat, copper and atrazine were used as primary stresses and mercury at a high concentration as a severe stress. None of the primary …
Folding induced supramolecular assembly into pH-responsive nanorods with a protein repellent shell
2018
We report the synthesis of ABA' triblock peptide-polysarcosine-peptide conjugates featuring two complementary phenylalanine-histidine pentapeptide strands A/A'. These sequences encode for antiparallel beta-sheet formation into folded conjugates, which promote the self-assembly into polysarcosine-shielded core-shell nanorods. These do not cause aggregation of serum proteins in human blood plasma underlining an enhanced stability.
Nanoscopic hybrid systems with a polarity-controlled gate-like scaffolding for the colorimetric signalling of long-chain carboxylates
2007
Hybrid mesoporous systems containing a gate-like ensemble functionalised with imidazolium groups and a dye are used for the selective colorimetric sensing of long-chain carboxylates. Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es
Chemistry of ?-hydridobis[pentacarbonylchromium(0)] species. Part III. Redox reactions with mercury(II) compounds and iodine
1981
[Cr2(CO)10(μ-H)]− undergoes ready hydride substitution on reaction with HgX2 (X = Cl, Br, I or SCN) or with iodine in acetone, yielding [Cr2(CO)10(μ-X)]− complex species which can be converted quantitatively into [Cr(CO)5X]− anions by reactions conducted in the presence of an excess of X−.
Concerted halogen and hydrogen bonding in [RuI2(H2dcbpy)(CO)2]···I2···(CH3OH)···I2···[RuI2(H2dcbpy)(CO)2].
2011
A new type of concerted halogen bond-hydrogen bond interaction was found in the solid state structure of [RuI(2)(H(2)dcbpy)(CO)(2)]···I(2)···(MeOH)···I(2)···[RuI(2)(H(2)dcbpy)(CO)(2)]. The iodine atoms of the two I(2) molecules interact simultaneously with each other and with the OH group of methanol of crystallization. The interaction was characterized by single crystal X-ray measurements and by computational charge density analysis based on DFT calculations.
Hydrogen-ion driven molecular motions in Cu2+-complexes of a ditopic phenanthrolinophane ligand
2004
One of the first kinetic evaluations of a metal ion interchange between the two coordination sites of a ditopic macrocycle is presented. Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es ; Soriano Soto, Concepción, Concepcion.Soriano@uv.es ; Verdejo Viu, Begoña, Begona.Verdejo@uv.es
Die pH-Statik als Hilfsmittel der Korrosionsforschung
1977
Die pH-Statik ist ein verhaltnismasig einfaches Verfahren zur Untersuchung von Korrosionsablaufen im pH-Bereich 2 – 9. Sie beruht darauf, das die Menge des verbrauchten Sauerstoffs (bei der Oxidation von Metallen) aquivalent der Menge der entstandenen Hydroxylionen ist. Bei dieser Arbeitsweise wird im oben erwahnten pH-Bereich ein bestimmter Wert eingestellt und durch Zugabe definierter Sauremenge konstant gehalten. Diese Korrelation wird am Beispiel von Kupfer in NaCl-Losung bestatigt, wobei der pH- Wert (4, 1) durch Zusatz von Salzsaure konstant gehalten wird. Die Reproduzierbarkeit der Messung ist abhangig von Temperatur, Sauerstoffpartialdruck und Ruhrgeschwindigkeit sowie von der Grose…
Neutral nido-heteroboranes with non ionisable hydrogen as arenes in coordination
2003
Designed ligands have been synthesised to produce the first arene-like metallacarborane. For arene-like coordination the number of electronegative elements on the coordinating site must be kept to a minimum. Choosing ligands with bulky substituents on the heteroatom allows easy rearrangement and arene-like coordination. This is more hampered the higher the number of hetereoatoms to be re-located.
Hydrogen influence on the structure and properties of amorphous hydrogenated carbon films deposited by direct ion beam
2008
Abstract The present work provides results for amorphous hydrogenated carbon (a-C:H) films grown by direct ion beam deposition method. Acetylene and its mixtures with hydrogen were used. The films were characterized by Rutherford backscattering spectrometry, elastic recoil detection, Raman spectroscopy, ellipsometry, infrared spectroscopy, and microhardness measurements. These techniques indicated that an admixture of hydrogen yields a lower deposition rate, a higher content of total and bounded hydrogen in the a-C:H films, and a lower film density. The optical and mechanical properties depend on both, hydrogen concentrations in the gas phase and in the films, and show a strong diamond-like…
Pd–Pt alloys: correlation between electronic structure and hydrogenation properties
2001
Abstract Palladium and its alloys have been extensively studied because of their faculty to store reversibly hydrogen isotopes. Here, the substitution of palladium with platinum is investigated. Thermodynamical studies have shown an anomalous behaviour regarding to the classical models. This original behaviour is explained by the study of the electronic structure of the binary solid solutions. The drastic decrease of the hydrogen solubility in the Pd–Pt alloys is accounted for by the filling up of the palladium conduction band by the valence electrons of platinum. The anomalous decrease of the stability of the hydride is explained by the large broadening of the valence band due to the subst…