M. Yu. Skripkin

Reversible chelating in acyclic diaminocarbene palladium complex containing hydrazide fragment

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.

Solution-solid phase equilibrium in the systems copper(II) halide-aprotic organic solvent-water

In the study of the solution-solid phase equilibrium in CuX2-S-H2O 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.

Solubility of d-elements salts in organic and aqueous-organic solvents: I. Copper, cobalt, and cadmium sulfates

Solubility at 25°C has been determined in the MSO4–H2O–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.

Solubility of d-element salts in organic and aqueous–organic solvents: II. Effect of halocomplex formation on solubility of cobalt bromide and chloride and nickel chloride

Solubility of salts in the systems MCl2–H2O–Solv (M = Co, Ni) and CoBr2–H2O–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.

Solubility of d-elements salts in organic and aqueous-organic solvents: III. Influence of intermolecular association on solubility of cadmium bromide and iodide

Solubility in the systems CdX2–H2O–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.

Organic solvent effect on the solution-solid phase equilibria in the systems CuCl2-L-H2O (L = DMSO, DMF, acetonitrile) at 25°C

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.

Adsorption of copper(II) ions from aqueous solutions on alumina industrial wastes

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 (NaHSO4, NaCl + HCl, and H2SO4) on the sorption activity of red mud was determined.

Effect of the oxidation state of copper on the solution-solid phase equilibria in CuClx-MCl-H2O systems

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.

Solubility of salts of d-elements in organic and water-organic solvents: V. Inner-sphere chalcogen S–S contacts in the [Ni(DMSO)4(H2O)2]Cl2 solvate

It was proved by the IR spectroscopy that the first coordination sphere of nickel cations in the NiCl2·2DMSO·9H2O, NiCl2·5DMSO·4H2O, and NiCl2·4DMSO·2H2O compounds contains dimethyl sulfoxide and water ligands. According to X-ray structural analysis, in crystals of the NiCl2·4DMSO·2H2O compound, noncovalent contacts between sulfur atoms of neighboring dimethyl sulfoxide molecules are realized in the inner sphere of the complex.

Solubility of d-elements salts in organic and aqueous-organic solvents: IV. Solubility of cadmium chloride

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.