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161.
A. Krause M. Uhlemann A. Gebert L. Schultz 《Journal of Solid State Electrochemistry》2007,11(6):679-685
The present work demonstrates the possibilities and the limits of the in situ electrochemical scanning tunneling microscopy
for investigation of nucleation processes in magnetic fields on the examples of Cu and Co electrodeposition onto Au(111) electrodes
from sulfate electrolytes with pH 3. Cyclic voltammograms of Cu in the underpotential range (UPD) exhibit no significant change
in the cathodic and anodic peaks recorded in magnetic fields parallel to the surface. In magnetic fields of a permanent magnet,
the reconstruction of Au has been annihilated during UPD of Cu. In the overpotential range, the dissolution of Cu is inhibited.
This triggers the formation of a Cu–Au surface alloy. The UPD deposition of Co onto Au(111) could be proven without magnetic
field, which leads to the formation of two monolayers. The nucleation in an applied field could not be observed due to higher
induced fluctuations and microconvective effects.
Contribution to special issue “Magnetic field effects in Electrochemistry”. 相似文献
162.
Four novel copper(Ⅱ) complexes have been synthesized,namely Cu(hfac)2NITPhNO2 (1),Cu(hfac)2NITPhCH3 (2),Cu(pfpr)2NITPhNO2,(3) and Cu(Pfpr)2NITPhCH3 (4),where hfac= hexafluoro-acetylacetonate,pfpr=pentafluoropropionate,NITR.=2-R-4,4,5,5-tetraniethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide.(R=4-nitrophenyl,4-methylphenyl).These complexes were rharicter-ized by elemental analyses,IR,electronic spectra and molar conductance.The temperature-dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4 300 K range,giving I he exchange integral J=10.56 cm-1 for complex 1 and J =-30.9 cm-1 for complex 3. 相似文献
163.
铜(II)-5-取代邻菲啰啉-二氧四胺大环三元体系的稳定性研究 总被引:1,自引:0,他引:1
The stability of copper (Ⅱ)-13-(2'-Hydroxy-3',5'-substituted benzyl)-1,4,8,11-tetraazacyclotetradecane-12, 14-dione(RTADO-14) binary complex compounds and of copper (Ⅱ)-5-substituted-1,10-phenanthrolines(R'TADO)-RTADO-14 ternary complex compounds was studied by means of pH titration method at 25.0±0.1 ℃ and I=0.1mol?dm-3KNO3. The formation constants of binary and ternary complexes were obtained. The structures of the binary and ternary complxes and the effects fo substituents on macrocyclic ligands and on R'Phen were also discussed. 相似文献
164.
Ivica Cepanec Mladen Litvi? Josipa Udikovi? Ivan Pogoreli? Marija Lovri? 《Tetrahedron》2007,63(25):5614-5621
Copper(I) triflate acts as an efficient stoichiometric reagent for the homo-coupling of aryldiazonium salts bearing electron-withdrawing group(s), to yield symmetrical biaryls in acetonitrile under mild reaction conditions. Aryldiazonium salts bearing electron-donating groups undergo the reaction by using catalytic amounts of a copper complex prepared in situ from copper(II) triflate and 2,2′-bipyridine with metallic copper as an ultimate reductant. 相似文献
165.
Treatment of [M(H2Li)] with UCl4 in pyridine led to the formation of the dinuclear complexes [MLi(py)UCl2(py)2] and/or [Hpy][MLi(py)UCl3] [Li = N,N′-bis(3-hydroxysalicylidene)-R, R = 1,2-phenylenediamine (i = 1), R = trans-1,2-cyclohexanediamine (i = 2), R = 2-amino-benzylamine (i = 3), R = 1,3-propanediamine (i = 4), R = 2,2-dimethyl-1,3-propanediamine (i = 5); M = Cu or Ni]. The crystal structures show that the 3d and 5f ions occupy, respectively, the N2O2 and O4 cavities of the Schiff base ligand, the U4+ ion adopting a dodecahedral or pentagonal bipyramidal configuration in the neutral and anionic complexes, respectively. 相似文献
166.
M. S. Abu-Bakr H. M. Rageh E. Y. Hashem M. H. Moustafa 《Monatshefte für Chemie / Chemical Monthly》1994,125(11):1197-1205
Summary The ternary complex formation of copper(II) with gallic acid (gal) and 2-hydroxy nicotinic acid (hyna), 2-mercapto nicotinic acid (mena), salicylic acid (sa) or thiosalicylic acid (tsa) as a second ligand in a 1:1:1 molar ratio has been investigated in 40% (v/v) ethanol using spectrophotometric andpH titration methods. The solution equilibria of the ternary systems have been determined and the stability constants of the mixed complexes has been evaluated. Considering all parameters, the Cu-gal-sa ternary system was proved as a suitable, rapid, and sensitive spectrophotometric indicator for determining traces of copper.The ternary system containingsa obeysBeer's law up to 3.4 µg·ml–1 copper. The optimum range for the determination of copper (Ringbom) atpH 6.0 ranges from 0.63 to 1.74 µg·ml–1 of copper. The molar absorptivity of the ternary complex is 1.3×104l·mol–1·cm–1.
Untersuchungen anmixed-ligand — Komplexen von Kupfer(II) mit 3,4,5-Trihydroxybenzoesäure und Pyridincarbonsäuren und ihren C-Homologen
Zusammenfassung Die Bildung ternärer Komplexe von Kupfer(II) mit 3,4,5-Trihydroxybenzoesäure (gal) und 2-Hydroxynicotinsäure (hyna), 2-Mercaptonicotinsäure (mena), Salicylsäure (sa) oder Thiosalicylsäure (tsa) in einem molaren Verhältnis von 1:1:1 wurde mittels spektrophotometrischer und potentiometrischer Methoden in 40% (v/v) Ethanol untersucht. Die Lösungsgleichgewichte der termären Systeme und die Stabilitätskonstanten der gemischten Komplexe wurden bestimmt. Unter Berücksichtigung aller Parameter erwies sich das termäre System Cu-gal-sa als geeigneter schneller und empfindlicher Indikator zur Spurenanalyse von Kupfer.Dassa enthaltende ternäre System gehorcht demBeerschen Gesetz bis zu einer Kupferkonzentration von 3.4 µg·ml–1. Der optimale Bereich zur Bestimmung von Kupfer (Ringbom) beipH 6.0 erstreckt sich von 0.63 bis 1.74 µg Cu pro ml. Die molare Extinktion des ternären Komplexes beträgt 1.3×104l·mol·cm–1.相似文献
167.
The adsorptive cathodic stripping voltammetry technique (AdCSV) is used to determine copper(II) using salicylaldehyde thiosemicarbazone (N, S- donor) as a complexing agent on hanging mercury drop electrode at pH 9.3. Variable factors affecting the response, i.e. the concentration of ligand, pH, adsorption potential and adsorption time are assessed and optimized. The adsorbed complex of copper(II) and salicylaldehyde thiosemicarbazone gives a well defined cathodic stripping peak current at −0.35 V, which has been used for the determination of copper in the concentration range of 7.85 × 10−9 to 8.00 × 10−6 M with accumulation time of 360 s at −0.1 V versus Ag/AgCl. This technique has been applied for the determination of copper in various digested samples of whole blood at trace levels. 相似文献
168.
By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C5H5N(C3H5)][Cu2Cl3] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) Å3 (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu4Cl62—)n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu2Cl3] ( 2 ), [L2Cu2Cl4] ( 3 ), and [LCuCl2] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle. 相似文献
169.
Copper(II) complex with
-piperidine-3-carboxylic acid (
-Hpipe-3):[Cu(
-pipe-3)2(H2O)] and cobalt(II) and nickel(II) complexes with piperidine-4-carboxylic acid (Hpipe-4):[M(Hpipe-4)2(H2O)4]Cl2 (M: Co, Ni) have been prepared and characterized by means of IR and powder diffuse reflection spectra, thermal analysis, and magnetic susceptibility. The crystal structures of these complexes have been determined by X-ray diffraction. The crystal of [Cu(
-pipe-3)2(H2O)] is orthorhombic with the space group Pbcn. The copper atom is in a square pyramidal geometry, ligated by two carboxylato oxygen atoms, two nitrogen atoms, and a water molecule. One molecule of this complex consists of either
-piperidine-3-carboxylic acid or
-piperidine-3-carboxylic acid. The crystals of [M(Hpipe-4)2(H2O)4]Cl2 are monoclinic with space group P21/n. In these complexes the metal atom is in an octahedral geometry ligated by two carboxylato oxygen atoms and four water molecules. 相似文献
170.
Graham A. Bowmaker Prof. Dr. Michael I. Bruce Brian W. Skelton Neil Somers Allan H. White 《无机化学与普通化学杂志》2007,633(7):1024-1030
The complexes [Cu2Br4]2?, [Cu2I4]2?, [Cu2I2Br2]2?, [Cu2I3Cl]2?, [Ag2Cl4]2? have been characterized as their isomorphous bis(triphenylphosphoranylidene)ammonium ([Ph3PNPPh3]+ = PNP+) salts by single crystal structural determinations. All anions show the centrosymmetric doubly halogen‐bridged forms [XM(μ‐X)2MX]2? with three‐coordinate metal atoms that have been observed in [M2X4]2? complexes with other large organic cations. In [Cu2I2Br2]2? the iodide ligands occupy the bridging positions and the bromide the terminal positions, while in [Cu2I3Cl]2?, obtained in an attempt to prepare [Cu2I2Cl2]2?, two of the iodide ligands occupy the bridging positions with the third iodide and the chloride ligand occupying two statistically disordered terminal positions. In [Ag2Cl4]2? the distortion from ideal trigonal coordination of the metal atom is greater than in the copper complexes, but less than in other previously reported [Ag2Cl4]2? complexes with organic cations. The ν(MX) bands have been assigned in the far‐IR spectra, and confirm previous observations regarding the unexpectedly simple IR spectra of [Cu2X4]2? complexes. 相似文献