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1.
Summary The interaction of PdII with DL-selenamethionine (SeMet) in acidic aqueous solution was investigated. SeMet was found to act as a bidentate ligand, forming a stable complex with PdII. Binding of the metal ion to the selenoether group creates a new chiral centre, which generates two sets of1H and13C n.m.r. methyl resonances for the two diastereoisomers. The2J values for (77Se–Me) decreased upon complex formation. 相似文献
2.
The preparation and structure of three trivalent plutonium chloride compounds from aqueous solution is reported. Two of the three are plutonium tetraaquatetrachloro complexes exhibiting a cis and a trans arrangement of Cl about the Pu. The identification of the coordination number of 4 with respect to Cl and the isomerism are both unprecedented in actinide solution chemistry. The third complex is a hexaaquadichloro complex of Pu(III), predicted by available thermodynamic data. 相似文献
3.
The sonochemical synthesis of stable palladium nanoparticles has been achieved by ultrasonic irradiation of palladium(II) nitrate solution. The starting solutions were prepared by the addition of different concentrations of palladium(II) nitrate in ethylene glycol and poly(vinylpyrrolidone) (PVP). The resulting mixtures were irradiated with ultrasonic 50 kHz waves in a glass vessel for 180 min. The UV-visible absorption spectroscopy and pH measurements revealed that the reduction of Pd(II) to metallic Pd has been successfully achieved and that the obtained suspensions have a long shelf life. The protective effect of PVP was studied using Fourier transform infrared (FT-IR) spectroscopy. It has been found that, in the presence of ethylene glycol, the stabilization of the nanoparticles results from the adsorption of the PVP chain on the palladium particle surface via the coordination of the PVP carbonyl group to the palladium atoms. The effect of the initial Pd(II) concentration on the Pd nanoparticle morphology has been investigated by transmission electron microscopy. It has been shown that the increase of the Pd(II)/PVP molar ratio from 0.13 x 10(-3) to 0.53 x 10(-3) decreases the number of palladium nanoparticles with a slight increase in particle size. For the highest Pd(II)/PVP value, 0.53 x 10(-3), the reduction reaction leads to the unexpected smallest nanoparticles in the form of aggregates. 相似文献
4.
The PMR technique has been used to establish the coordinations in 1 : 1 and 1: 2 Pd(II) to glycyl-L-aspartic acid complexes. In the 1 : 1 complex both nitrogens and the α-carboxyl group are coordinated to the metal ion and the β-carboxyl group is in a pseudoaxial position. In the 1 : 2 complex only nitrogen atoms are coordinated to Pd(II) ions and the conformations of the ligands in this complex are also established. 相似文献
5.
Palladium(I) carbonyl chloride (PdCOCl) n has been synthesized by the effect of CO on PdCl2 in the presence of trace water. Anionic palladium(I) carbonyl chloride has been synthesized during treatment of ethanol-based or acetone-based solutions of H2PdCI4 containing small amounts of water; it has been isolated from the solution as the salt Cs2[Pd2(CO)2Cl4]. IR-spectra, X-ray diffraction patterns, and thermogravimetry data on synthesized palladium(I) carbonyl complexes are presented. 相似文献
6.
Summary Platinum(II) and palladium(II) chloride complexes with purine, pyrimidine (pyrimid),N-ethylimidazole(N-EtIm) andN-propylimidazole(N-PropIm) ligands have been prepared and characterized by analysis and spectroscopic methods. The compounds have general formula M(L1)(L2)Cl2 where M=PtII, PdII; L1=purine or pyrimid, L2=N-EtIm orN-PropIm, except the complexes Pt(purine)(pyrimid)Cl2 and [Pd(purine)(pyrimid)2Cl]Cl and [Pt(purine)2 (N-propIm)Cl]Cl·2H2O. 相似文献
7.
L. Fuks N. Sadlej-Sosnowska K. Samochocka W. Starosta 《Journal of Molecular Structure》2005,740(1-3):229-235
Equilibrium geometries of platinum(II) and palladium(II) tetrathiourea dichlorides have been determined by the X-Ray diffraction studies as well as calculated by the Density Functional Theory using the MPW1PW/LanL2DZ functional/basis set. Infrared spectra of the species have also been studied in the 4000–400 cm−1 frequency range both experimentally and theoretically. The experimental and theoretical data remain in satisfactory agreement. 相似文献
8.
Stylianou M Drouza C Viskadourakis Z Giapintzakis J Keramidas AD 《Dalton transactions (Cambridge, England : 2003)》2008,(44):6188-6204
The reaction of Cu2+ acetate monohydrate with 2-[N,N'-bis(carboxymethyl)aminomethyl]-4-carboxyphenol (H4cacp), 2-[N,N-bis(carboxymethyl)aminomethyl]hydroquinone (H4cah) and the dinucleating 2,5-bis[N,N-bis(carboxymethyl)aminomethyl]hydroquinone (H6bicah) in water results in the formation of several Cu2+ species, which are in dynamic equilibrium in aqueous solution and their stability is pH dependent. A systematic crystallographic study of these species was pursued, resulting in the characterization of most of the species. Additional techniques were employed to characterize the molecules in the solid state (infrared spectroscopy) and in solution (UV-vis spectroscopy and electrochemistry). These measurements show that the Cu2+ ions are ligated mainly to the iminodiacetate at pH < 6, exhibiting only weak interactions with the phenol oxygen. At pH > 6, the phenol oxygen was deprotonated and dinuclear-bridged species, from the phenolate oxygen complexes exhibiting a Cu2+ 2O2 core, were isolated. The coordination environment around the copper ions varies between trigonal bipyramidal, tetragonal pyramidal and distorted octahedral geometries. The two unpaired electrons of the Cu2+ ions are found to be antiferromagnetically coupled. A survey of the magnetic and structural properties of the dinuclear phenoxide bridged Cu2+ complexes shows that the strength of the antiferromagnetic coupling is linearly dependent on the Cu-Ophenolate bond lengths, at bond distances below 1.98 angstroms. The effect of the Cu-O-Cu angles on the magnetic properties of the complexes is also discussed. 相似文献
9.
Chester M. Mikulski Scott Grossman Chung Ja Lee Nicholas M. Karayannis 《Transition Metal Chemistry》1987,12(1):21-25
Summary Complexes of the general types Pd(L)(LH)Cl (LH=hxH, xnH, or tbH) and Pt(L)(LH)Cl3 (LH=hxH, or xnH) are formed by boiling under reflux 21 molar mixtures of hypoxanthine (hxH), xanthine (xnH) or theobromine (tbH) and PdCl2 or PtCl4 in ethanol-triethyl orthoformate. These complexes appear to be linear chain polymeric species, characterized by single monoanionic L– ligands bridging between adjacent Pd2+ or Pt4+ ions. Inclusion of one terminal neutral LH and one terminal chloro-ligand completes the coordination sphere in the square-planar Pd2+ complexes, while the Pt4+ complexes aretrans-octahedral, involving three terminal chloro and one terminal LH ligand per platinum. The possible binding sites of the bidentate bridging L– and the unidentate terminal LH are discussed. 相似文献
10.
B3LYP/6-31++G(d,p) optimizations on models for the metal cyanin, Cy, complexes [MCy(H2O) n ]+, (M = Zn(II), Cu(II); n = 2, 3, 4) in aqueous solution indicate that 4 is the most favoured coordination number in both cases. SP -4 and T -4 geometries are nearly isoenergetic for the former, while SP -4 is the only one obtained for the latter. Anionic cyanin displays higher affinity for Cu(II) than for Zn(II) or Mg(II). The electron density reorganization of cyanin model accompanying the complexation process was analyzed by means of the quantum theory of atoms in molecules. This analysis reveals that: (1) the O4′–M bond is stronger than O3′–M; (2) anionic cyanin displays a dual character between 4′-keto-quinoidal and 3′,4′-dienolate resonance forms; (3) Cu(II) takes more electron density than Zn(II) from Cy? and water ligands; (4) when the coordination number increases, each ligand (Cy? or water) transfers less electron density; (5) complex formation modifies the electron density in all the atoms of the ligands, but the largest modifications are displayed within the AC bicycle of Cy?; and (6) a third part of density lost by the Cy? ligand is removed from hydrogens. 相似文献
11.
The preparation and properties of a new, weakly basic ion-exchanger containing suilonylguanidine as the active groups are described. Palladium and platinum chlorides can be quantitatively separated by this resin. Under certain conditions platinum does not react with the resin, whereas palladium is adsorbed and can then be eluted with 3 M hydrochloric acid. 相似文献
12.
N. Sabbatini M. Ciano S. Dellonte A. Bonazzi V. Balzani 《Chemical physics letters》1982,90(4):265-268
The absorption spectrum of the complex between Eu2+ and the [2.2.2] cryptand shows narrow, weak transitions within 4f7 superimposed on broad, strong transitions from 4f7 to 4f6 5d. Emission from 4f65d to 4f7 can be observed at 77 K λmax = 420 nm, τ = 0.55 μs) and at 293 K (λmax = 460 nm, τ = 3 ns) in aqueous solution. 相似文献
13.
E. E. Kern D. K. Anderson 《Journal of polymer science. Part A, Polymer chemistry》1968,6(10):2765-2772
Diffusion and anisotropic electrical conductivity measurements have been used to investigate the structure of poly(methacrylic acid) in aqueous solution at various degrees of neutralization. Both kinds of measurement indicate that the polyion chain opens from a coiled to an extended configuration as the chain is neutralized. In addition it was found that, at low concentrations, the opening of the chain is a two-step process, whereas at higher concentrations the mechanism involves a single step. 相似文献
14.
L. A. Brusnitsyna T. A. Alekseeva E. I. Stepanovskikh A. O. Osipchuk 《Russian Journal of Applied Chemistry》2016,89(9):1414-1420
A study of the possibility of optimizing the efficiency of a catalytic palladium layer demonstrated that the minimum palladium adsorption providing a sufficient catalytic activity of the surface is Γmin = 3.178 × 10–6 mol m–2, which can be reached at a palladium dichloride concentration of 0.035 g L–1. It was shown that palladium(II) activates the surface of the insulator (is sorbed) from a true, rather than a colloid solution. 相似文献
15.
Cariati F Caruso U Centore R Marcolli W De Maria A Panunzi B Roviello A Tuzi A 《Inorganic chemistry》2002,41(25):6597-6603
Two new N-salicylidene-N'-aroylhydrazines ligands have been prepared: N-4-diethylaminosalicylidene-N'-4-nitrobenzoyl-hydrazine (L(1)) and N-4-diethylaminosalicylidene-N'-4-(4-nitrophenylethylidene)-benzoyl-hydrazine (L(2)). The ligands are properly functionalized with strong electron donor-acceptor groups and are of potential interest in second-order nonlinear optics (NLO). Dimeric copper(II) and palladium(II) complexes with L(1) and L(2) have been prepared, and, starting from these, mononuclear acentric adducts with pyridine as a further ligand have been prepared and characterized. The X-ray structures of three adducts are also reported. The NLO activity of the adducts has been determined by EFISH measurements giving mubeta values up to 1500 x 10(-48) esu for an incident wavelength of 1.907 microm. 相似文献
16.
Q. -S. Ye M. -J. Xie W. -P. Liu W. -Zh. Xia X. -Zh. Chen Q. -W. Chang Y. Yu 《Journal of Structural Chemistry》2011,52(1):212-215
Diammine(malonato)palladium(II) is synthesized by the reaction of [Pd(NH3)4](NO3)2 with malonic acid, and its crystal structure is determined by single crystal X-ray diffraction. Distorted coordination square
of the Pd(II) atom is formed by two N atoms of two ammonia molecules and two O atoms of bidentate malonate ligand. The average
Pd-N and Pd-O distances are 2.018(7) ? and 2.014(2) ?, respectively. The molecules are stacked in such a way that the planes
of coordination squares are parallel with the Pd...Pd distances between the nearest neighbors in a stack of 4.039 ?. 相似文献
17.
A copper(II) ion-selective-electrode potentiometric method was used to determine the first and second hydrolysis constants of Cu2+. Special techniques prevented copper(II) hydroxide precipitation, and copper(II) carbonate and cipper(II) organic complexation during the titration of the experimental solution over the pH range 6.8–8.4. The large change in the total copper concentration during the titration due to adsorption of copper onto the vessel walls was accounted for by measuring the total copper concentration at each pH by atomic absorption spectrophotometry. The two hydrolysis constants were determined at 25°C in 0.7 and 0.05m NaClO4 media. The measured stability constants are independent of the copper concentration and yield similar zero ionic strength values. Also, the stepwise equilibrium constants decrease as the ligand number increases. 相似文献
18.
G. V. Afanas’eva T. I. Bychkova V. G. Shtyrlin A. R. Shakirova A. V. Zakharov 《Russian Journal of General Chemistry》2006,76(5):757-765
Solvation and complexation of Cu(II), Ni(II), and Co(II) with adipic acid dihydrazide (L) in aqueous and aqueous-ethanol solutions (ethanol mole fraction 0.07–0.68) were studied by spectrophotometry. The formation constants of the species M(LH)3+, ML2+, M2L4+ (μ = Cu2+, Ni2+, Co2+), and also M2L 2 4+ and ML 2 2+ (μ = Cu2+, Ni2+) were determined. With Cu(II), the complexes Cu(LH) 2 4+ , CuL(LH)3+, and Cu2L(LH)5+ were also detected and characterized. Evidence is given for the hydrazide coordination mode: tridentate in ML2+, bidentate in M(LH)3+ and ML 2 2+ , and tetradentate in M2L4+ and M2L 2 4+ . The ligand exchange reactions involving CuL2+, Cu(LH)3+, Cu(LH) 2 4+ , CuL(LH)3+, CuL 2 2+ , and Cu2L(LH)5+ in aqueous solutions of Cu(II) were revealed and kinetically characterized by nuclear magnetic relaxation. The heretofore unknown rate constants of formation of these complexes were calculated from the thermodynamic and kinetic parameters. Factors controlling the rate constants of the complex formation and chemical exchange are discussed. 相似文献
19.
20.
Nilsson KB Maliarik M Persson I Fischer A Ullström AS Eriksson L Sandström M 《Inorganic chemistry》2008,47(6):1953-1964
The ammonia solvated mercury(II) ion has been structurally characterized in solution by means of EXAFS, (199)Hg NMR, and Raman spectroscopy and in solid solvates by combining results from X-ray single crystal and powder diffraction, thermogravimetry, differential scanning calorimetry, EXAFS, and Raman spectroscopy. Crystalline tetraamminemercury(II) perchlorate, [Hg(NH3)4](ClO4)2, precipitates from both liquid ammonia and aqueous ammonia solution, containing tetraamminemercury(II) complexes. The orthorhombic space group ( Pnma) imposes C s symmetry on the tetraamminemercury(II) complexes, which is lost at a phase transition at about 220 K. The Hg-N bond distances are 2.175(14), 2.255(16), and 2 x 2.277(9) A, with a wide N-Hg-N angle between the two shortest Hg-N bonds, 122.1(7) degrees , at ambient temperature. A similar distorted tetrahedral coordination geometry is maintained in liquid ammonia and aqueous ammonia solutions with the mean Hg-N bond distances 2.225(12) and 2.226(6) A, respectively. When heated to 400 K the solid tetraamminemercury(II) perchlorate decomposes to diamminemercury(II) perchlorate, [Hg(NH3)2](ClO4)2, with the mean Hg-N bond distance 2.055(6) A in a linear N-Hg-N unit. The mercury atoms in the latter compound form a tetrahedral network, connected by perchlorate oxygen atoms, with the closest Hg...Hg distance being 3.420(3) A. The preferential solvation and coordination changes of the mercury(II) ion in aqueous ammonia, by varying the total NH 3:Hg(II) mole ratio from 0 to 130, were followed by (199)Hg NMR. Solid [Hg(NH 3)4](ClO4)2 precipitates while [Hg(H2O)6](2+) ions remain in solution at mole ratios below 3-4, while at high mole ratios, [Hg(NH3)4](2+) complexes dominate in solution. The principal bands in the vibrational spectrum of the [Hg(NH3)4](2+) complex have been assigned. 相似文献