Sorption of Nickel Ions from Aqueous Solutions by Ion Exchangers

Sorption of Ni²⁺ions from aqueous solutions by ion exchangers differed in their chemical nature and structure was studied. Based on the endothermic curves of ice melting obtained by a differential scanning calorimetry, the amounts of freezing and non-freezing water present in free volumes (pores) of the studied ion exchangers were calculated. Comparison of results obtained from the kinetic curves of nickel ion sorption with data on differential scanning calorimetry indicates a role of structural factor in the sorption of nickel ions. It was found that, depending on the total amount of freezing and non-freezing water, the KU-2-8 sulfonated cationite is the most preferable ion exchanger for the sorption of nickel ions from aqueous solutions. Therefore, sorbent efficiency in this case is determined by its structure rather than by chemical nature.     

Ion-exchange recovery of nickel(II) and cobalt(II) from sulfuric acid solutions

Sorption recovery of nickel(II) and cobalt(II) in their joint presence in sulfuric acid solutions was studied on new samples of domestic ion exchangers of CYBBER brand. It was shown that the ion exchangers under study have a high sorption capacity for ions of both nonferrous metals, depending on the structure of a sorbent and on the acidity of a contacting solution. It was found that, after Co(II) and Ni(II) ions are extracted from weak or strong sulfuric acid solutions, they can be effectively eluted from the ion exchangers under study with a 2 M hydrochloric acid solution to an extent of 85–95% (nickel) and 87–95% (cobalt).     

Mobility of Ni(II) Ions in Inorganic Ion Exchangers Based on Zirconium Hydroxophosphate

The mobility of Ni(II) ions in inorganic ion exchangers based on zirconium hydroxophosphate with varying phosphorus content was studied using electromigration and kinetic methods. It was found that the effective diffusion coefficient of nickel in the ion exchanger phase increased with increasing phosphorus content within the range 1·10^–13 to 2·10^–12 m²/s.     

Regioselective Nucleophilic Functionalization of Antiaromatic Nickel(II) Norcorroles

Treatment of antiaromatic nickel(II) norcorrole with potassium cyanide provided nickel(II) 3‐cyanonorcorrole with perfect regioselectivity without the help of a catalyst. The reaction of the nickel(II) norcorrole with phenol or thiophenol in the presence of a base also yielded substitution products. The antiaromatic 16π conjugation system in the norcorrole core was preserved in the functionalized products. Introduction of phenylthio groups significantly decreased the HOMO–LUMO gap and enhanced the near IR absorption property.     

Simultaneous Determination of Nickel(II) and Cobalt(II) by Second-Derivative Spectrophotometry

4-(2-Pyridylazo) resorcinol, PAR, is shown to be useful for simultaneous determination of cobalt(II) and nickel(II) using second-derivative spectrophotometric method with controlled experimental parameters. This method allows the determination of 0.20-1.25 ppm of nickel(II) and 0.25-1.50 ppm of cobalt(II) in mixtures with good precision and accuracy. This method has advantages of simplicity, speed and requires no prior separations.     

Symmetric and Unsymmetric Nickel(II) Schiff Base Complexes; Metal-Localized Versus Ligand-Localized Oxidation

The oxidation of symmetric and unsymmetric nickel(II) Schiff base complexes was examined in acetonitrile by cyclic voltammetry. Unlike nickel(II) bis(salicylaldimine) complexes which undergo oxidative polymerization at the electrode surface, the complexes examined in this study contain at least one β-ketoimine chelate and are irreversibly oxidized at the electrode surface. The mixed chelate complexes are oxidized at potentials midway between those of the symmetric bis(salicylaldimine) and bis(β-ketoimine) complexes, suggesting a metal-localized rather than a ligand-localized oxidation. Oxidation of nickel(II) to nickel(III) followed by rapid intramolecular electron transfer to give reactive ligand-radical species is proposed to explain the irreversible oxidation of the nickel(II) Schiff base complexes.     

Nickel(II) and copper(II) complexes of 5-substituted-salicylaldehyde thiosemicarbazones

Binuclear nickel(II) and copper(II) complexes with four 5-methoxysalicylaldehyde N(3)-substituted thiosemicarbazones and nickel(II) complexes of four 5-nitro-salicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic, and e.s.r. spectra of the complexes, as well as i.r., electronic, and 1H- and 13C-n.m.r spectra of the thiosemicarbazones, have been obtained. None of these compounds show significant growth inhibitory activity against the fungi Aspergillus niger and Paecilomyces variotii.     

Nanocomposites of Metallic Silver with Octamolybdate Amine Complexes of Nickel(II) and Copper(II)

Theoretical and Experimental Chemistry - It was shown that interaction of photoreduced octamolybdate amine complexes of nickel(II) and copper(II) with silver(I) nitrate in aqueous solutions leads...     

Facile Template Synthesis in the System Ni(II)-Dithiooxamide-Acetaldehyde on Gelatin-immobilized Nickel(II) Hexacyanoferrate Matrices

Template synthesis of a nickel(II) chelate with an (N'N'S'S)-donor ligand, 4'6-dimethyl-2'8-di-thio-3'7-diaza-5-oxanonanedithioamide-1'9, with a metal ion:ligand ratio of 1:1 is realized in getalin-immobilized nickel(II) hexacyanoferrate(II) matrices contacting with aqueous solutions containing dithiox-amide, acetaldehyde (pH > 10), where the latter two compounds play the role of ligand synthons. On directcontact of dithioxamide and acetaldehyde in the solution in the absence of Ni(II), the above (N,N,S,S)-donorligand does not form, and no nickel(II) chelates with this ligand can be obtained by reactions of known nickel(II) dithiooxamide complexes with acetaldehyde.     

Spectrophotometric Determination of Cobalt(II), Nickel(II) and Copper(II) with Acenaphthenequinone Monosemicarbazone (AQSC)

Cobalt(II), nickel(II) and copper(II) complexation with acenaphthenequinone monosemicarbazone (AQSC) has been studied spectrophotometrically. The Co(II), Ni(II) and Cu(II) complexes are soluble in ethanol medium and exhibit maximum absorbance at 410, 420 and 430 nm, respectively. The sensitivity of the reactions are 0.012, 0.02 and 0.01 μg/cm² for cobalt, nickel and copper systems. All the three complexes show maximum and constant absorbance in the pH range 8.4 to 9.8, 6.3 to 8.4 and 5.4 to 8.0 for Co-AQSC, Ni-AQSC and Cu-AQSC, respectively. Nickel and copper in some alloys have also been analysed.     

Use of Carbonate-Containing Industrial Waste for Treatment of Aqueous Solutions To Remove Nickel(II) Ions

The possibility of using a carbonate-containing industrial waste formed in water-treatment units of thermal power plants for treatment of aqueous solutions to remove nickel(II) ions was analyzed. The influence exerted by the time, temperature, and other factors on the degree of recovery of nickel(II) ions and sorbent expenditure was established. The possibility of separating nickel(II) and iron(III) ions simultaneously present in solution, using the waste under study, was demonstrated.     

Pentanuclear Nickel(II) Complex with two Vertex-Shared Triaminoguanidine Fragments and Symmetric Capping Ligand

The pentanuclear nickel(II) complex [Ni₅(saltag^Br)₂(tptz)₄] ( Ni5 ) with the tritopic triaminoguanidine-derived Schiff-base ligand H₅saltag^Br (1,2,3-tris[(5-bromosalicylidene)amino]guanidine) and tptz (2,4,6-tris(2-pyridyl)-1,3,5-triazine) as capping ligands is reported. Ni5 crystallizes in the triclinic space group P1 with the central nickel(II) ion linking two triangular arrangements of nickel(II) ions supported by two tritopic triaminoguanidine ligands. The octahedral coordination of the four peripheral nickel(II) ions is complemented by capping tridentate tptz ligands. By variation of the synthesis also the corresponding trinuclear nickel(II) complex [Ni₃(saltag^Br)(tptz)₃]NO₃ ( Ni3 ) is accessible. Magnetic measurements for Ni3 and Ni5 reveal a singlet ground state with antiferromagnetic coupling between the nickel(II) ions, which in the case of Ni5 can only be simulated assuming a two-J exchange coupled spin topology. For both complexes significant zero-field splitting for the nickel(II) ions is evident from the measured magnetic data, which can be verified by theoretical studies revealing a magnetic anisotropy with strong rhombic distortion due to the presence of the tptz co-ligands in both compounds.     

Nickel(II) Complexes Bearing 4-Arylimino-1,2,3-trihydroacridines: Synthesis,Characterization, and Ethylene Oligomerization

Nickel(II) complexes have attracted much attention as a new generation of olefin catalysts since the α-diiminonickel complex was discovered as a highly efficient procatalyst for ethylene polymerization. A series of novel 4-arylimino-1,2,3-trihydroacridylnickel(II) dihalide complexes was synthesized in a one-pot reaction of 2,3-dihydroacridine-4-one and different anilines with nickel(II) chloride or nickel(II) bromide 1,2-dimethoxyethane complex. The complexes were characterized by infrared spectroscopy and elemental analysis. The molecular structures of the representative complexes 4-(2,6-diisopropylphenylimino)-1,2,3-trihydroacridylnickel(II) dichloride (C3), 4-(2,4,6-trimethylphenylimino)-1,2,3-trihydroacridylnickel dichloride(II) (C4), and 4-(2,4,6-trimethylphenylimino)-1,2,3-trihydroacridylnickel(II) dibromide (C9) were confirmed by single-crystal X-ray crystallography, revealing a distorted tetrahedral geometry around the nickel(II) of C3 and distorted trigonal bipyramidal geometry for C4 and C9. With the activation of trimethylaluminium (TMA), all nickel(II) complexes exhibited good activity for ethylene oligomerization, and oligomer products ranged from butene (C₄) to hexadecene (C₁₆).     

Nickel(II) complexes of β-N-alkylimme arylhydrazones

Summary -N-alkylimine arylhydrazone ligand complexes of nickel(II) have been synthesised by metal template reactions. The azomethine nitrogen and the a-nitrogen of the arylhydrazone coordinate to the metal with square-planar geometry around the nickel(II) ion. Structures have been proposed based on the spectral properties of the complexes.Reprints of this article are not available.     

Novel use of doublet peaks in flow injection analysis : Simultaneous Spectrophotometric Determination of Nickel(II) and Iron(II)

A simple, non-separation method for the simultaneous, single-injection determination of nickel(II) and iron(II) is described. The method is based on doublet peaks in a single-line system, with multiple vertical (absorbance) measurements of the doublet peak profile. Doublet peaks occur when the center of the sample zone remains unmixed. Nickel(II), 0.17–0.24 M, in the presence of 2.7–5.4 mM iron(II) is determined by direct spectrophotometry of the nickel(II) ion at the center of the sample zone, Iron(II) is first oxidized on-line by peroxodisulfate to iron(III), which complexes with thiocyanate to form the intensely red complex; this is measured at the peak maximum corresponding to the trailing edge of the sample zone. Correction are made for absorbance of nickel and its reduction in the iron thiocyanate complex formation. The absorbance of nickel(II) ion and the iron thiocyanate complex are both measured at 395 nm from a single injected sample. The general utility of the doublet peak method is discussed.     

Nickel(II) Oxide Solubility and Phase Stability in High Temperature Aqueous Solutions

A platinum-lined, flowing autoclave facility was used to investigate the solubility behavior of nickel(II) oxide (NiO) in deoxygenated ammonium and sodium hydroxide solutions, between 21 and 315°C. Solubilities were found to vary between 0.4 and 400 nmol-kg^–1. The measured nickel ion solubilities were interpreted via a Ni(II) ion hydroxo- and ammino-complexing model, and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. Two solid phase transformations were observed: at temperatures below 149°C, the activity of Ni(II) ions in aqueous solution was controlled by a hydrous Ni(II) oxide (theophrastite) solid phase rather than by anhydrous NiO (bunsenite); above 247°C, Ni(II) activities were controlled by cubic rather than by rhombohedral bunsenite.     

Nickel(II) complexes of substituted diphenylcarbazones and their adducts with heterocyclic nitrogen bases

The complexing behaviour of novel 1,5-di(4-chloro-2- methylphenyl)carbazone and 1,5-di(2,4-dichlorophenyl)carbazone towards nickel(II) ions has been investigated by elemental analysis, magnetic susceptibility, u.v. -vis., i.r. and 1H-n.m.r. spectral studies. The ligands act as bidentate N,O donors and form 1:2 complexes with the metal ions. The adducting behaviour of nickel(II) complexes with nitrogen bases has been studied spectrophotometrically in a chloroform monophase. The nickel(II) di(4-chloro-2-methylphenyl)carbazonate forms hexacoordinate adducts with monodentate and bidentate bases with 1:2 and 1:1 chelate:base stoichiometries, respectively, whilst, nickel(II) di(2,4-dichloro-phenyl)carbazonate forms penta- and hexacoordinate adducts of 1:1 chelate:base stoichiometry with monodentate and bidentate bases, respectively. The results are discussed on the basis of steric properties and the basicity of the nitrogen bases.     

Structure and Kinetics of Oxidation of Amphiphilic Nickel(II) Pentaazamacrocycles by Peroxodisulfate and by a Nickel(III) Pendant-Arm Macrocycle

Three nickel(II) pentaazamacrocycles bearing pendant alkyl tails have been synthesized,and the crystal structure of one (bearing an octyl tail) is reported. The redox potentials of the complexes, for oxidation of the nickel(II) centre, is 0.72 V (versus S.H.E.) in all cases, indicating that the pendant alkyl tails have no effect on the redox site. The kinetics of oxidation of the complexes by peroxodisulfate, S₂O₈ ^2- and by aqua(5, 5, 7,12, 12, 14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-acetato)nickel(III),[Ni(hmca)(OH₂)]²⁺ have been studied. Oxidation by S₂O₈ ^2- occursby ion-pairing of the reactants, followed by electron transfer with concomitant peroxo bond fissure. Oxidation by [Ni(hmca)(OH₂)]²⁺ occurs by an outer sphere electron transfer process. Redox kinetics at the nickel centre provides a probe for supramolecular interactions at the pendant tails in such complexes.     

Nickel(II) and cobalt(II) complexes of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe)

Nickel(II) and cobalt(II) bis-chelates of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe) were synthesized and characterized by spectroscopic methods and in the case of the nickel complex, X-ray single-crystal diffraction. The ligand exhibits the (N, S) coordination mode on interacting with the metal centers. The X-ray structure of the nickel(II) complex reveals a NiN₂S₂ distorted square planar coordination geometry with the ligands showing a cis configuration. There is no interaction between the –CH₂COOMe moieties of the ligand and the metal center, however intermolecular hydrogen bonds through the carbonyl group leads to the building of dimeric associations.     

异薄荷醇黄原酸镍的配合物(英)

The coordination geometry around Ni atom in the homochiral bis(2-isopropyl-5-methylcyclohexyl xanthalato) nickel(Ⅱ) (1) displays an approximately square plane defined by four S atoms from two xanthalato ligands. CCDC: 252343.