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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.
Palladium nanoparticles stabilized by poly(N-vinyl-2-pyrrolidone) (PVP) are efficient catalysts for the Suzuki reactions in aqueous medium. The time dependence of the fluorescence intensity of the biphenyl product in the reaction between iodobenzene and phenylboronic acid is used to determine the initial rate of the catalytic reaction. The initial rate depends linearly on the concentration of Pd catalyst, suggesting that the catalytic reaction occurs on the surface of the Pd nanoparticles. 相似文献
3.
The thermal decomposition of commercially available aqueous solutions of manganese(II) nitrate was investigated using the conventional thermal analytical techniques of thermogravimetry (TG), differential thermal analysis (DTA), and evolved gas analysis (EGA). Infrared spectra and X-ray diffraction patterns were used to help characterize intermediate species. 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.
Floriana Vitale Rosa Vitaliano Ilaria Fratoddi Emanuela Piscopiello Maria Vittoria Russo 《Journal of organometallic chemistry》2008,693(6):1043-1048
This work is focused on the synthesis of innovative hybrids made by linking gold nanoparticles to protected organometallic Pd(II) thiolate. The organometallic protected Pd(II) thiolate, i.e. trans-thioacetate-ethynylphenyl-bis(tributylphosphine)palladium(II) has been synthesized, in situ deprotected and linked to Au nanoparticles. In this way new hybrid, with a direct link between Pd(II) and Au nanoparticles through a single S bridge, has been isolated. The combination of the organometallic Pd(II) thiol with gold nanoparticles allows the enhancement and tailoring of electronic and optical properties of the new organic-inorganic nano-compound. Single-crystal gold nanoparticles, uniform in shape and size were obtained by applying a modified two-phase method (improved Brust-Schiffrin reaction). In addition, the chemical environment of the Au nanoparticles was investigated and a covalent bonding between Au nanoparticles and the organometallic thiols was observed. 相似文献
6.
Lengke MF Fleet ME Southam G 《Langmuir : the ACS journal of surfaces and colloids》2007,23(17):8982-8987
The interaction of cyanobacterial biomass (Plectonema boryanum UTEX 485) with aqueous palladium(II) chloride (PdCl2 degrees ) has been investigated at 25-100 degrees C for up to 28 days. We report that the release of organic materials from the cyanobacteria promoted the precipitation of Pd(0) as crystalline spherical and elongate nanoparticles (< or =30 nm), both in solution and as dispersed and encrusted nanoparticles on cyanobacterial cells. In contrast, under abiotic conditions at 100 degrees C, palladium hydride (PdHx) was the principal palladium phase precipitated, with only minor amounts of palladium metal. 相似文献
7.
S. G. Vul'fson A. N. Glebov I. G. Nagaitseva O. Yu. Tarasov Yu. I. Sal'nikov A. N. Vereshchagin 《Russian Chemical Bulletin》1990,39(11):2237-2240
The composition, stability, and structure of palladium(II) chloride complexes in hydrochloric acid media have been determined using nuclear-magnetic relaxation, magnetochemical methods, and Rayleigh light scattering. The predominant form in solution for palladium(II) concentrations greater than 0.005 moles/liter is the octahedral Pd6Cl12 or Pd6Cl14
2–, which has antiferromagnetic properties in contrast with the paramagnetic properties of the mononuclear aquachloride. The polarizability anisotropy of Pd-Cl bonds with terminal and bridging chlorine atoms has been determined.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2473–2477, November, 1990. 相似文献
8.
Tae Hwan Noh Sung Min Kim Kyung Hwan Park Ok-Sang Jung 《Transition Metal Chemistry》2012,37(6):535-540
The crystal structures of the well-known complexes, [(Me4en)M(II)X2] (Me4en?=?N,N,N??,N??-tetramethylethylenediamine; M(II)?=?Pd(II) or Pt(II); X ??=?NO2 ? or NO3 ?) have been determined. For [(Me4en)Pd(NO2)2] and [(Me4en)Pt(NO2)2], the nitrite anion acts as a monodentate N-donor ligand in the solid state. In contrast, for [(Me4en)Pd(ONO2)(O2NO)], the two nitrate anions act as a monodentate O-donor (ONO2) and a bidentate O,O??-donor (O2NO). Recrystallization of [(Me4en)Pt(NO3)2] from Me2SO yields the Me2SO adduct with a monodentate O-donor nitrate and a counteranionic nitrate, [(Me4en)Pt(ONO2)(S-Me2SO)](NO3). The solution behavior of these complexes, including the equilibrium between coordinated and free Me2SO, has been investigated. 相似文献
9.
Yong-jia Shang Jian-wei Wu Chen-li Fan Jin-song Hu Ben-ye Lu 《Journal of organometallic chemistry》2008,693(18):2963-2966
The first synthesis and characterization of 1,3-bis-(5-ferrocenylisoxazole-3-yl) benzene-derived palladium(II) acetate complex were described and its application in Heck coupling reactions in an aqueous solution was studied. Complex 5 had been demonstrated to be a highly stable, active and efficient catalyst for Mizoroki-Heck coupling reactions. 相似文献
10.
Suzuki coupling is one of the most powerful methods for the synthesis of biaryls. We have prepared and characterized a series
of unsymmetrical sulfonated water-soluble Pd(II)-pyridyl imine complexes and investigated them as catalysts for the Suzuki
cross-coupling reaction in water under microwave irradiation. The compounds proved to be effective catalysts. 相似文献
11.
12.
The stability of hexacyanoferrate(II)-amine(methylamine, ethylenediamine, diethylenetriamine and tetraethylenepentamine) was determined potentiometrically. Species Fe(CN)6(A)H
j
(j–4)
(A=amine) are formed in all the systems investigated, with j=1...n+2 (n=number of aminogroups). Some other complexes Fe(CN)6(A)iHj (with i>1) were also found. The stability of these complexes is fairly high: the full protonated amine species, show for the reaction Fe(CN)6
4- + HnAn+ = Fe(CN)6(A)Hn
(n-4) an equilibrium constant given by logK=0.686+2.10n. Factors affecting the stability are discussed in comparison with similar systems, together with the importance of interferences. 相似文献
13.
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
14.
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
15.
A method of synthesis of the organic-inorganic nanocomposite consisting of a paraformaldehyde matrix and aluminum oxide nanoparticles is developed. Spontaneous dispersion of the composite in water at various component ratios makes it possible to prepare a sol or gel of hydrated aluminum oxide. No changes in the oxide particle dimensions are observed during storage of the composite. 相似文献
16.
We report on the synthesis of highly monodisperse iron nanoparticles, using a chemical reduction method. Iron nanoparticles with an average diameter of 6 nm and a geometric standard deviation of 1.3 were synthesized at a pH of 9.50 from ferric chloride precursor with sodium borohydride as the reducing agent, polyacrylic acid as the dispersing agent, and palladium ions as seeds for iron nanoparticle nucleation. The resulting nanoparticles were ferromagnetic at 5 K and superparamagnetic at 350 K. The dispersing agent polyacrylic acid (PAA) was shown to prevent iron nanoparticles and possibly palladium clusters from aggregating; in the absence of PAA, only aggregated iron nanoparticles were obtained. The addition of palladium ions decreased the diameter of iron nanoparticles presumably by providing sites for heterogeneous nucleation onto palladium clusters. In the absence of palladium ions, the mean diameter of iron nanoparticles was approximately 110 nm and the standard deviation increased to 2.0. The pH of the solution also was found to have a significant effect on the particle diameter, likely by affecting PAA ionization and altering the conformation of the polymer chains. At lower pH (8.75), the PAA is less ionized and its ability to disperse palladium clusters is reduced, so the number of palladium seeds decreases. Therefore, the resulting iron nanoparticles were larger, 59 nm in diameter, versus 6 nm for nanoparticles formed at a pH of 9.50. 相似文献
17.
In this research, the herbaceous peat collected from Gavurgolu peatlands, one of the biggest Turkish peatlands, was utilized as an adsorbent for the removal of copper (II) ions from aqueous solution. Adsorption experiments were conducted under various conditions, i.e., initial concentration, temperature, and pH. While the amount of Cu (II) adsorbed on the peat increased with increasing concentration of Cu (II) ions, it was not markedly affected by temperature and pH. Percentage removal was higher at lower concentration. For example, the maximum percentage removal of Cu (II) ions for initial concentration of 3 x 10(-4) M was 97.04% at 21 degrees C and pH 5.5. The adsorption capacity (Q(0)) of the peat was 4.84 mgg(-1) from Langmuir adsorption isotherm for the concentration range of 3 x 10(-4)-6 x 10(-4) M at 21 degrees C and pH 5.5. The equilibrium time of adsorption of Cu (II) ions was 150 min and independent of concentration and temperature. The amount of Cu (II) adsorbed at equilibrium time did not considerably change with temperature and pH. It was also determined that adsorption isotherm followed both Freundlich and Langmuir. Uptake mechanism of Cu (II) ions by the peat occurs via cation exchange (especially by means of Ca(2+) and Mg(2+)) as well as copper/peat complexation. Adsorption kinetic was consistent with the pseudo-second-order model. 相似文献
18.
19.
Palladium and nickel complexes with tetrabenzoporphine were synthesized by reacting tetrabenzoporphine and cadmium tetrabensoporphine with palladium and nickel chlorides in boiling dimethylformamide and identified. 相似文献
20.
D. L. Selin N. P. Tarasova A. V. Malkov G. A. Poskrebyshev 《Reaction Kinetics and Catalysis Letters》1989,39(2):273-278
-radiation of Co60 has been applied to reduce Eu(III) to Eu(II) in aqueous solutions of the mixture of rare earths. The kinetics of the process has been investigated as a function of the absorbed radiation dose and organic additive concentration.
+3 - Co60: Eu(III)Eu(II). .相似文献