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The stability constants of the complexes of europium(III) and terbium(III) ions with terephthalic acid anions were determined by potentiometric titration over a wide pH range. The luminescent properties of these complexes were studied. It was shown that the complexes are most stable in slightly acidic solutions. Analysis of the photoluminescence emission spectra confirmed the adequacy of the proposed model of complexation. [ABSTRACT FROM AUTHOR]

The stability constants of triply charged lanthanide ion complexes with citric acid of 1 : 2 stoichiometry were measured by potentiometric titration in a wide pH range, and the relationship between the constants and the lanthanide type was analyzed. A mathematical model for the equilibrium in studied solutions was proposed. [ABSTRACT FROM AUTHOR]

Nanocrystalline NaGd1–xNdxF4 (x = 0–1)phosphors have been synthesized by hydrothermal synthesis for the first time. All synthesized compounds have hexagonal β-NaYF4 crystalline phase. Neodymium(III) ions isomorphically replace gadolinium ions. NaGd0.96Nd0.04F4 compound has the largest photoemission intensity in NIR range upon 808-nm excitation; further doping with Nd3+ results in concentration quenching. [ABSTRACT FROM AUTHOR]

Microcrystalline phosphors NaY0.8–xYb0.2HoxF4 (x = 0–0.1) were first synthesized by the hydrothermal method. All synthesized compounds have hexagonal β-NaYF4 crystalline phase. It has been found that holmium(III) ions isomorphically replace yttrium ions. The maximum intensity of up-conversion emission in the visible region of the spectrum upon 973-nm excitation is observed for the compound NaY0.78Yb0.2Ho0.02F4. [ABSTRACT FROM AUTHOR]

The nanocrystalline phosphor NaGd0.7Eu0.3F4 with the most intensive luminescence among NaGd1–xEuxF4 (x = 0–1) compounds was obtained by hydrothermal synthesis. The unit cell parameters and nanoparticle size were determined. The cytotoxicity, luminescent, and magnetic properties were characterized. [ABSTRACT FROM AUTHOR]

New microcrystalline phosphors NaY1–xTbxF4 (x = 0–0.6) were obtained by the hydrothermal synthesis. All compounds have the hexagonal β-NaYF4 crystalline phase. Terbium(III) ions isomorphically replace yttrium ions, which results in increasing the unit cell parameters and decreasing the particle size. The maximum luminescence intensity is observed for the NaY0.6Tb0.4F4 compound. [ABSTRACT FROM AUTHOR]

The complex formation of nickel(II) and copper(II) ions with 4,4′-bipyridine in non-aqueous solvents—dimethyl sulfoxide, dimethylformamide, dimethylacetamide, acetonitrile, ethanol and methanol was studied by UV-Vis absorption spectroscopy. Stability constants of the resulting complexes were calculated. [ABSTRACT FROM AUTHOR]

Microcrystalline anti-Stokes luminophores NaY1–x–y–zYbxEryLuzF4 were obtained for the first time by hydrothermal synthesis. These compounds crystallize in the hexagonal crystal system, structural type β-NaYF4. It was found that the addition of a non-luminescent lutetium(III) ions results in up-conversion luminescence enhancement in more than 2 times upon 980 nm excitation. [ABSTRACT FROM AUTHOR]

Solutions of tetraethylammonium phthalate in non-aqueous solvents (ethanol, dimethylsulfoxide, dimethylformamide, and acetonitrile) were studied by electronic absorption spectroscopy. It was shown that the phthalate anion dimerizes in acetonitrile and dimethylformamide solutions due to π-stacking, the experimental equilibrium constants being 550±50 and 900±50, respectively. Dimerization of the phthalate anion was not observed in ethanol and dimethylsulfoxide solutions. [ABSTRACT FROM AUTHOR]

The electronic absorption spectra of cobalt(II) complexes with 4,4′-bipyridine in non-aqueous solvents were recorded, and the stability constants of these complexes were determined. The values of stability constants decrease as the donor numbers of solvents increase. [ABSTRACT FROM AUTHOR]

The influence of ionic interactions in ternary aqueous and aqueous-organic solutions of metal halides on the structure of the solid phases in equilibrium with the solutions is analyzed. An original classification of double and complex salts, reflecting the peculiarities of their structure, is given. The conditions for the formation of various types of these compounds are determined. The factors that determine the preservation of the metal ion surrounding during the solution-solid phase transition are revealed. [ABSTRACT FROM AUTHOR]

The results of the study of ternary systems containing copper, cobalt, nickel, and cadmium halides and sulfates in binary water-organic and mixed organic solvents are summarized. The influence of the donor-acceptor properties of the ternary system components, the relative dielectric permittivity, and the intermolecular association in the mixed solvent on the solubility of salts and the crystalline structure of solvates is analyzed. [ABSTRACT FROM AUTHOR]

Four complexes [Ni(DMA)2(H2O)4]Cl2·2H2O, [Ni(DMF)2(H2O)4]Cl2·2H2O, and [Ni(DMA)6][NiCl4], [Ni(DMF)2(H2O)2Cl2] were isolated from ternary water-organic saline systems containing nickel chloride and N, N-dimethylacetamide-water and N, N-dimethylformamide-water binary solvents. The obtained complexes were studied by X-ray structural analysis. The formation of hydrogen bonds between water molecules of the nickel ion solvate sphere, chloride ions, and non-coordinated water molecules located in the cavity of the crystal structure was detected. [ABSTRACT FROM AUTHOR]

Electronic spectra of copper(II) phthalate complexes in non-aqueous solvents were obtained. Stability constants of the complexes were determined. It was shown that the stability constants and the donor numbers of the solvents are in inverse relation to each other. [ABSTRACT FROM AUTHOR]

Solutions of tetraethylammonium and lithium chlorides in acetonitrile were studied by electronic absorption spectroscopy. It was shown that at concentrations up to 100 mmol/L tetraethylammonium chloride completely dissociates. The association constant of lithium chloride in acetonitrile (Kass = 4800 mol–1 L) was determined by the spectrophotometric method. The electronic absorption spectra of the Li+Cl– ionic pair and Cl– anion in acetonitrile were studied. [ABSTRACT FROM AUTHOR]

Solubility of copper(II) chloride at 25°C in binary organic solvents consisting of dimethyl sulfoxide, N,N-dimethylacetamide, and 1,4-dioxane was determined by the isothermal saturation method. The shape of solubility isotherms for all ternary systems under study is connected with the structural type of formed copper chloride solvates, the composition of which is defined by the solvent donor number. Solvates crystallize predominantly, where the metal ion coordinates molecules of the solvent with a greater donor power. The temperature increase in the system CuCl2-dimethylacetamide-dioxane up to 50°C leads to the formation of the cluster compound [Cu4Cl6O(DMA)4]; its structure was determined by the X-ray structural analysis method. [ABSTRACT FROM AUTHOR]

Five solvates, [CdBr2(DMF)]n, [CdBr2(DMA)]n, [CdI2(DMF)]n, [Cd(DMF)6][Cd2I6], and {[Cd(DMA)6][Cd5I12]n}m, were isolated from the ternary systems CdX2-L-H2O (X = Br, I; L = N,N-dimethylacetamide, N,N-dimethylformamide) and characterized by the X-ray single crystal analysis. The structures of the first three solvates is similar to each other in structures and represent a one-dimensional polymer chain, the fourth solvate has the discrete structure containing [Cd(DMF)6]2+ and [Cd2I6]2- ions, and the fifth solvate contains discrete [Cd(DMA)6]2+ cations and the polymer anionic fragment [Cd5I12]n 2n-. [ABSTRACT FROM AUTHOR]

Solubility of cadmium chloride at 25°C in four ternary systems containing mixed water-organic solvents was measured by the isothermal saturation method. Dimethyl sulfoxide, N, N-dimethylacetamide, N, N-dimethylformamide, and 1,4-dioxane were used as organic components. In all systems the organic component addition provides a salting-out effect within the whole range of the binary solvent compositions. [ABSTRACT FROM AUTHOR]

Solubility in the systems CdX-HO-Solv (X = Br, I; Solv = dimethyl sulfoxide, N,N-dimethyl acetamide, N,N-dimethyl formamide, and 1,4-dioxane) at 25°C was measured by the isothermal saturation method. A relation between the shape of the solubility isotherm and the structure of the binary solvent depending on its composition was found. Positions of solubility maxima and isotherms inflection points in the most cases correlate with destruction of intermolecular associates formed by solvent components. [ABSTRACT FROM AUTHOR]

Solubility of salts in the systems MCl-HO-Solv (M = Co, Ni) and CoBr-HO-Solv (Solv = dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide) at 25°C was measured experimentally. Dominating species of cobalt and nickel halides existing in various concentration regions were identified by analysis of electron absorption spectra. It was shown that the major factor defining solubility is the interaction of halocomplexes of metal ions with solvent molecules. [ABSTRACT FROM AUTHOR]

Solubility at 25°C has been determined in the MSO-HO-Solv systems (M = Co, Cu, or Cd; Solv = dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, tetrahydrofuran, or dioxane) via the isothermal saturation method. Analysis of the solubility as function of the permittivity and donor power of solvents along with the information on the cations radius leads to the conclusion that ion-ion association dominates over solvation interactions in the studied systems. [ABSTRACT FROM AUTHOR]

Study of molar conductivity of several palladium(II) complexes has revealed that cationic acyclic diaminocarbene complexes of palladium(II) containing carbohydrazide fragment in the carbene ligand are capable of reversible cyclization to form a six-membered C,O-chelate. This process is favored by factors enhancing dissociation of the anionic ligand in the starting neutral compound. DFT simulation of cationic carbene complexes of palladium has confirmed possibility of such chelating. [ABSTRACT FROM AUTHOR]

In the study of the solution-solid phase equilibrium in CuX-S-HO system (X = Cl, Br, S = dimethyl sulfoxide, N, N-dimethylformamide, tetrahydrofuran, 1,4-dioxane) at 25°C we established the effect of the solvent properties and the type of the halide ligand (dielectric premeability, donor number, hydrophobicity) on the solubility of the solid phase in binary and ternary systems, the length of the fields of crystallization of the compounds and the structure of the water-organic solvates. [ABSTRACT FROM AUTHOR]

Equilibrium adsorption of copper(II) ions on red mud (alumina industrial wastes) modified by various methods was studied. The effect exerted by the nature the modifier (NaHSO, NaCl + HCl, and HSO) on the sorption activity of red mud was determined. [ABSTRACT FROM AUTHOR]

Absorption spectra of NRBr-HO and CoBr-NRBr-HO (R = Et, Bu) aqueous solutions were measured within the range of 1000-25000 cm, and the influence of tetraalkylammonium cations on the equilibrium between cobalt octahedral and tetrahedral complexes was revealed. The specificity of hydration interactions in solutions under study in various concentration ranges and resulting from them difference in spectral characteristics were analyzed. Variously directed changes in positions of bands in the region of stretching vibrations, a composite frequency of 5200 cm, and the first water overtone occurring due to the concentration variation were found. [ABSTRACT FROM AUTHOR]

Solubility in the ternary systems MgBr-NRBr-HO (R = Me, Et, Bu) at 25°C was determined by the isothermal saturation method. A comparative analysis of phase diagrams was fulfilled. The results obtained were interpreted in the context of competition between hydration and association processes in water-salt systems. The structure of double salts NMeBr·MgBr·6HO and NEtBr·MgBr·8HO was determined, and the possibility for predicting compositions of crystallizing double salts on the basis of crystallographic characteristics of ions was analyzed. [ABSTRACT FROM AUTHOR]

By the hydration of MVO(SeO) with saturated water vapors at room temperature a series of isostructural complex compounds of vanadium(V) of the composition M[VO(SeO)(HO)]·HO (K, Rb, NH) are synthesized and their physicochemical properties are studied. Based on the X-ray and neutron diffraction data, it is found that their crystal structure is composed of VO octahedra linked in infinite chains by bridging SeO tetrahedra. Each of the VO octahedra has two short terminal V-O bonds forming a bent dioxovanadium group VO. Two water molecules are coordinated by vanadium and one molecule is out of the first coordination sphere in the interchain space. The vibrational spectra of the studied compounds are completely consistent with their structural features. [ABSTRACT FROM AUTHOR]

Results of an experimental research of phase equilibrium in ternary systems MX-NRX-HO [M = Cd(II), Cu(II), Co(II), Mg(II); X = Cl, Br; R = Me, Et, Bu] at 25°C were reported. A comparative analysis of compositions of solid compounds and regions of their crystallization, which are equilibrium with liquid phase, was conducted. An effect of hydration, association of salts of quaternary ammonium and acido complexation of ions of d-elements on the formation of the complex and double salts in the systems was presented. [ABSTRACT FROM AUTHOR]

Solubility of the ternary systems M-NEtCl-HO (M = Cd, Cu, Co) at 25°C was determined by the method of isothermal saturation. Compositions and fields of crystallization of solid compounds in equilibrium with a liquid phase were determined. Changes in the processes of hydration, association of tetraethyl ammonium salts, and acido-complex formation of d-element ions on the replacement of a halide anion affect the solution-solid phase equilibria in the studied systems. [ABSTRACT FROM AUTHOR]

The solubility diagrams in ternary MBr-NRBr-HO systems (M = Cd, Co; R = Me, Et, Bu) at 25°C were determined by isothermal saturation. The composition and crystallization range of solid compounds occurring in equilibrium with the liquid phase were found. The effects of ion hydration, association of tetraalkylammonium salts, and complex formation with d-elements on the solution-solid phase equilibrium were estimated. [ABSTRACT FROM AUTHOR]

The crystalline structures of four tetraethylammonium salts, [EtN]CdBrP, [EtN]CdBr, [EtN]CoBr, and [EtN]CuBr were determined by X-ray analysis of their single crystals. The CdBr anions in the examined salts are linked to polymeric chains, and the coordination number of cadmium ion is 5 or 6. The d-metal ion in the copper and cobalt complexes has tetrahedral configuration, and the corresponding anions are discrete. [ABSTRACT FROM AUTHOR]

A solution-solid equilibrium in ternary water-organic systems CuCl2-L-H2O (L = dimethyl sulfoxide, N,N-dimethyl formamide, and acetonitrile) at 25°C was studied. The expansion of crystallization branches of individual solvates CuCl2· xL varies in parallel to the donor power of organic solvents. The existence of the mixed crystal-solvates CuCl2·2H2O·2(CH3)2SO, CuCl2·2H2O·2(CH3)2NCHO, CuCl2·H2O·(CH3)2NCHO, CuCl2·2H2O·CH3CN, and CuCl2·3H2O·2CH3CN in the studied systems was proved. Various donor power of oxygen-containing solvents determines the composition of the first coordination sphere of the copper ion in the specified compounds: the coordination of the both solvents in the mixed crystal-solvates with DMF and the absence of water in the nearest environment of the copper(II) ions in the CuCl2·2H2O·2(CH3)2SO compound. [ABSTRACT FROM AUTHOR]

The solubility of d-metal halides in MCl2-M′Cl2-H2O systems with competitive complex formation at 25°C was discussed. The role of complex formation and hydration was traced. As the stability constants become closer to each other, the salting-in regions in the crystallization braches of both chlorides disappear. [ABSTRACT FROM AUTHOR]

The effect of the oxidation state of the metal on the solubility was analyzed using the example of CuClx-MCl-H2O ( x = 1, 2; M = Li-Cs, NH4) ternary systems. The prevalence of acido complex formation is responsible for an essential similarity of the solubility isotherms: the presence of crystallization branches of complex salts and salting-in (or weak salting-out) of copper(I) and (II) chlorides, that increases in the order LiCl < NaCl < KCl < CsCl. The different stability of copper(I) and (II) chloride complexes results in that the chemical individuality of alkali metal cations is differently reflected in the shape of the solubility isotherms: The stronger complex formation in copper(I) systems results in leveling of this effect and the weaker complex formation with copper(II), in its differentiation. [ABSTRACT FROM AUTHOR]

Solubility in the systems of CuCl-LiCl-HO and CuCl-CsCl-HO at 25°C was studied by the method of isothermal removal of oversaturation. The results were examined in terms of the competition between hydration and complex formation processes in water-salt systems. [ABSTRACT FROM AUTHOR]

Solubility in the system CuBr-CdBr-HO at 25°C was determined by the method of isothermal saturation. The obtained data were examined from the viewpoint of competitive formation of acido complexes in aqueous solutions. [ABSTRACT FROM AUTHOR]

It was proved by the IR spectroscopy that the first coordination sphere of nickel cations in the NiCl·2DMSO·9HO, NiCl·5DMSO·4HO, and NiCl·4DMSO·2HO compounds contains dimethyl sulfoxide and water ligands. According to X-ray structural analysis, in crystals of the NiCl·4DMSO·2HO compound, noncovalent contacts between sulfur atoms of neighboring dimethyl sulfoxide molecules are realized in the inner sphere of the complex. [ABSTRACT FROM AUTHOR]

The nanocrystalline phosphor NaGd0.7Eu0.3F4 with the most intensive luminescence among NaGd1–xEuxF4 (x = 0–1) compounds was obtained by hydrothermal synthesis. The unit cell parameters and nanoparticle size were determined. The cytotoxicity, luminescent, and magnetic properties were characterized. [ABSTRACT FROM AUTHOR]