Search results for "AH"
showing 10 items of 6917 documents
Tin(IV) complexes with O-ethyl(N-ethyl-N,N-dimethylammoniomethyl)phosphonate
1999
Abstract O,O-Diethyl-(N,N-dimethylaminomethyl)phosphonate undergoes ethyl migration leading to O-ethyl-(N-ethyl-N,N-dimethylammoniomethyl)phosphonate (L). Several new complexes of tin(IV) and organotin(IV) chlorides with the title ligand have been synthesized. The stoichiometry of the obtained complexes is as follows: (R3SnCl)2 · L (R=Me, Bu, Ph), R2SnCl2 · L (R=Me, Bu, Ph), RSnCl3 L (R=Me, Ph) and SnCl4 · L. All the complexes have been studied in solution by means of 1H-, 13C-, 31P- and 119Sn-NMR spectroscopy. Their solid state structures have been investigated by means of Mossbauer spectroscopy and the molecular structure of the complex (Ph3SnCl)2 · L has been determined by X-ray crystall…
A Combined Experimental and Theoretical Study on Bis(μ‐alkoxo)diiron(III) Complexes with Hydroxybenzylaminoethanol [O,N,O] Donor Ligands: Syntheses, …
2011
Three new neutral bis(μ-alkoxo)diiron(III) complexes were prepared from N(R),N-(2-methylene-4,6-di-tert-butylphenol)aminoethan-1-ol ligands (H2L1, R = Me and H2L2, R = H). In these complexes, the ligand wraps around the metal center exhibiting a tridentate facial coordination mode with alkoxo-bridging oxygen, amine nitrogen and phenoxo oxygen donor atoms. In the complex [Fe(acac)L1]2·MeCN (1) acetylacetonato coligand complete the distorted octahedral coordination spheres of the iron(III) ions, whereas in the five-coordinate iron(III) chloride complexes [FeClL1]2 (2) and [FeClL2]2 (3) the ligands induce a geometry that is intermediate between square pyramidal and trigonal bipyramidal. Magnet…
Synthesis, crystal structure and magnetic properties of a new [ZnII6DyIII6] dodecanuclear motif
2013
Abstract A new dodecanuclear complex, [{(HL)(L)(dmf)ZnIIDyIII(dmf)(H2O)}6]·3dmf·4.2H2O has been assembled using a supramolecular compartmental ligand (H3L results from the condensation reaction of 3-formylsalicylic acid and hydroxylamine). The six DyIII ions describe an octahedron that is inscribed into the octahedron generated by the zinc(II) ions each DyIII ion from this motif behaving as a single ion magnet.
Crystal structure and mössbauer spectroscopy studies of the ferrimagnetic complex bimetallic salt hexaamminechromium (III) hexachloroferrate (III), […
1992
The crystal and molecular structures of the ferrimagnetic bimetallic complex salt hexaamminechromium(III) hexachloroferrate(III), [Cr(NH3)6][FeCl6], have been determined from single-crystal, three-dimensional x-ray diffraction counter data. The compound crystallizes as orange coloured crystals in the space groupC2/c of the monoclinic system with Z=4 and has cell dimensionsa=11.325(1) A,b=11.387(1) A,c=11.233(1) A, and β=90.83(1)A. The structure was refined by using segmented block diagonal least-squares techniques to discrepancy indices R and Rw of 0.0233 and 0.0285, respectively. The metal ions occupy sites with symmetry $$\bar 1$$ and are nearly octahedrally coordinated. In the [FeCl6]3− …
Organoelement derivatives of steroids: synthesis and structural characterization of diorganotin chloride adducts of hormones
1986
Abstract Ten new diorganotin dichloride adducts of hormones of the type R 2 SnCl 2 ·2L [where R = Me, Et, n-Bu, Oct and Ph; L = 4-androsten-17s-ol-3-one ( A ); 5-androsten-3s-ol-17-one ( B ); 4-androsten-17α- methyl-17s-ol-3-one ( C ) and 3,17-dihydroxy-5- pregnene-20-one ( D )] have been prepared and characterized at 297 K and 223 K. Spectroscopic measurements (IR; Raman; 1 H, 13 C, 119 Sn NMR) suggest the dissociation or fast ligand exchange in solution at 297 K. Hexa-coordinated adducts with bonding through carbonyl oxygen and trans -R groups in octahedral geometry are formulated at 223 K.
Superparamagnetic iron oxide/oleic acid nanoparticles with immobilized organosilicon derivatives ofN-(2-hydroxyethyl)tetrahydroisoquinoline: synthesi…
2013
Superparamagnetic iron oxide/oleic acid nanoparticles bearing lipid-like organosilicon N-(2-hydroxyethyl)-1,2,3,4-tetrahydroisoquinoline derivatives have been synthesized with the aim of their potential biomedical application. X-ray diffraction analysis, Dynamic light-scattering measurements, method of magnetogranulometry and some others have been employed to investigate the morphology and properties of the nanoparticles synthesized. The magnetic core diameter of mixed covered nanoparticles ranged between 4.8 and 9.6 nm. The magnetization analyses showed that the particles are superparamagnetic at room temperature. In vitro cell cytotoxicity and intracellular NO generation caused by the wat…
Nanoelectron spectroscopy for chemical analysis: a novel energy filter for imaging x-ray photoemission spectroscopy
2005
An ovel instrument for imaging ESCA is described. It is based on a tandem arrangement of two hemispherical energy analysers used as an imaging energy filter. The main spherical aberration (α 2 -term) of the analyser is corrected by the antisymmetry of the tandem configuration. The kinetic energy range useable for imaging extends up to 1.6 keV; this is compatible with Mg and Al Kα laboratory x-ray sources. First experiments on the chemical surface composition of a Cu0.98Bi0.02 polycrystal, a GaAs/AlGaAs heterostructure and Ag crystallites on Si(111) have been performed using synchrotron radiation. The results reveal an energy resolutio no f190 meV and a lateral resolution (edge resolution) o…
One-dimensional oxalato-bridged copper(II) complexes with 3-hydroxypyridine and 2-amino-4-methylpyridine
2001
Two new one-dimensional oxalato-bridged copper(II) compounds of formula [Cu(ox)L2]n (1) and {[Cu2(ox)2L%3]·L%}n (2) [ox oxalate dianion, L3-hydroxypyridine (pyOH) and L% 2-amino-4-methylpyridine (ampy)] have been synthesized and characterized by FT-IR spectroscopy, variable-temperature magnetic measurements and single-crystal X-ray diffraction. The crystal structure of 1 comprises chains of copper atoms in which cis-[Cu(pyOH)2] 2 units are sequentially bridged by asymmetric bis-bidentate oxalato ligands with an intrachain copper‐copper separation of 5.548(1) A, . Each copper atom is six-coordinated: four oxygen atoms belonging to two bridging oxalato ligands and two nitrogen atoms from two …
Microwave emission related to cyclotron instabilities in a minimum-Belectron cyclotron resonance ion source plasma
2015
Electron cyclotron resonance ion sources (ECRIS) have been essential in the research and applications of nuclear physics over the past 40 years. They are extensively used in a wide range of large-scale accelerator facilities for the production of highly charged heavy ion beams of stable and radioactive elements. ECRISs are susceptible to kinetic instabilities due to resonance heating mechanism leading to anisotropic electron velocity distribution function. Instabilities of cyclotron type are a proven cause of frequently observed periodic bursts of 'hot' electrons and bremsstrahlung, accompanied with emission of microwave radiation and followed by considerable drop of multiply charged ions c…
Multi-technical approach for the characterization of polychrome decorative surfaces at Spanish Mission Churches in Nueva Vizcaya (Chihuahua, Mexico)
2020
An interdisciplinary and multi-institutional group of science and art conservation specialists has provided new insight into the painting materials used in the polychrome walls and wooden ceilings in four seventeenth century Spanish colonial churches of Nueva Vizcaya (Chihuahua, Mexico). A multi-analytical study of the decorative surfaces was performed in situ using spectroscopic approaches (XRF, FORS), False Colour Infrared Reflectography – IRFC, as well as micro sampling for ATR-FTIR, LM and GC/MS laboratory analyses. A survey of natural resources were also studied by ATR-FTIR and LM to elucidate the natural occurrence of a select number of materials found in the surrounding areas of the …