Search results for "METALS"
showing 10 items of 2013 documents
Encapsulation of Et3N+–H···OH2 in a hydrogen-bonded resorcarene capsule
2000
In the crystalline state a resorcarene dimer linked by ten hydrogen-bonding water molecules encapsulates the hydrogen-bonded complex Et3N+–H···OH2 while bromide anions are positioned outside the cavity.
ESI-FTICR investigation of triethylammonium ion-driven resorcin[4]arene dimer formation and structure
2002
In the course of mass spectrometric measurements a self-assembled hydrogen bonded resorcinarene dimer was observed, the formation of which was driven by the binding of triethylammonium ion as a guest and as an ionic label.
In situ measurement of elastic properties of PdH , PdD , and PdT
2003
Abstract The Young’s modulus E of palladium hydride PdH x , deuteride PdD x and tritide PdT x were measured for studying the effect of both hydrogen stoichiometry x and isotope nature. A special technique based on optical detection of flexural modes of a palladium cylindrical microcantilever was adapted to in situ measurements to guarantee the sample homogeneity during the hydriding process. A 10% decrease in E was found between pure polycrystalline palladium and hydride phases. The non linear dependence observed with the H content was discussed in terms of lattice expansion, phonons and electronic properties. Sensitivity of the technique enables to distinguish an isotope effect on E .
Hydrogen bonded calixarene capsules kinetically stable in DMSO.
2002
Half-life times up to 4 days in DMSO at room temperature are observed for the decomposition of dimeric capsules of urea substituted calix[4]arenes held together by a combination of hydrogen bonds, mechanical entanglement and cation–π interactions.
Hydrogen induced metallization of ZnO (11̅00) surface: Ab initio study
2014
Abstract Results of first principles hybrid calculations are presented for hydrogen atoms adsorbed upon non-polar ZnO (1100) surface. The energy of surface atomic relaxation, H adsorption energy, electronic density redistribution and modification of the electronic structure are discussed. It is shown that hydrogen is adsorbed mainly on the surface oxygen ions and forms a strong bonding with them (2.7 eV). Adsorption of hydrogen on the surface zinc ions is energetically unfavorable (− 4.4 eV). It also shown that surface hydrogen atoms are very shallow donors, thus, contributing to the electronic conductivity, and ZnO metallization.
Highly dispersed encapsulated AuPd nanoparticles on ordered mesoporous carbons for the direct synthesis of H2O2 from molecular oxygen and hydrogen
2012
AuPd nanoparticles (<3 nm) have been encapsulated on the pores of a nanostructured CMK-3 carbon prepared by a nanocasting procedure. This material has been shown to be an excellent catalyst for the direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen.
Encapsulation of diquats by resorcinarenes: a novel staggered anion–solvent mediated hydrogen bonded capsule
2002
Crystallisation studies of ethyl resorcinarene with diquats 2b and 3a (1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane dibromide and 1,4-diazoniabicyclo[2.2.2]octane dichloride, respectively) resulted in hydrogen bonded molecular capsules in which the cations are encapsulated in between the cavities of two resorcinarene molecules and anions are located in the middle of the lower rim ethyl chains.
Pyrogallarenes as alkali metal receptors: the role of cation-pi interactions in complexation.
2006
Crystallization studies of C-methyl pyrogallarene with potassium, rubidium and caesium bromides or chlorides resulted in a hydrogen bonded molecular cage in which the alkali metal cations are eta6 coordinated to aromatic rings via strong cation-pi interactions.
Hydrogen-bonded dimers of a thiacalixarene substituted by carbamoylmethylphosphineoxide groups at the wide rim.
2006
A thiacalix[4]arene derivative bearing four carbamoylmethylphosphineoxide groups at the wide rim forms hydrogen-bonded, dimeric capsules with S8 symmetry in the crystalline state and in apolar solvents, where the inclusion of cationic guests could be proved by 1H NMR and ESI mass spectra.
Sediment origin and pedogenesis in the former mill pond basin of Turznice (north-central Poland) based on magnetic susceptibility measurements
2016
Abstract This paper aims to assess the usefulness of magnetic susceptibility measurements in pedological studies of mill pond sediments. The study area includes the former Turznice mill pond basin located in the south-eastern part of the Grudziądz Basin. Four soil profiles were selected within the transect located along the longitudinal axis of the basin. The following soil properties were determined in the collected samples: bulk density, particle size distribution, pH, content of carbonates, approximate content of organic matter (LOI), total organic carbon (TOC), total nitrogen (Nt), and the pseudo-total contents of metals (Fe, Mn, Cu, Zn, Pb, Ni, Cd). The obtained results were correlated…