


Vol 62, No 4 (2017)
- Year: 2017
- Articles: 21
- URL: https://journal-vniispk.ru/0036-0236/issue/view/10227
Synthesis and Properties of Inorganic Compounds
An improved method for the synthesis of [ZnW12O40]6– and its reaction with [Pt(OH)4(H2O)2]: Crystal structures of (H2NMe2)5H[ZnW12O40] · 3.5H2O and K6Na2[PtW6O24] · 11H2O
Abstract
(Me2NH2)5H[ZnW12O40] · 3.5H2O (I) has been synthesized by the reaction between Zn(NO3)2 · 4H2O, Na2WO4 · 2H2O and (Me2NH2)NO3 under hydrothermal conditions with a yield of 79%. The crystal structure of complex I has been characterized by single-crystal X-ray diffraction. Crystals of complex I are monoclinic, space group Cc, a = 13.165(1) Å, b = 19.370(1) Å, c = 20.987(2) Å, α = 84.81°, V = 5145.9(0) Å3, Z = 4, C10H48N5O43.5ZnW12. The Zn–O and W–O bond lengths are 1.86(2)–1.89(3) and 1.697(1)–2.030(2) Å, respectively. Na2K6[PtW6O24] · 11H2O (II) has been synthesized by a slow reaction between (Me2NH2)5H[ZnW12O40] · 3.5H2O and [Pt(OH)4(H2O)2] in H2O at room temperature. Crystals of complex II are trigonal, space group R\(\bar 3\)m, a = 13.138(1) Å, c = 20.987(2) Å, V = 2742.9(1) Å3, Z = 3, H22O35Na2K6PtW6. The crystal structure of complex II contains [PtW6O24]6– anions linked to K+ cations via oxygen atoms. The Na+ cation is coordinated to water molecules. The Pt atom is in a standard octahedral surrounding (Pt–O and W–O are 2.018(6) and 1.762(5)–2.151(4) Å, respectively).



Coprecipitation of calcium hydroxyapatite, graphene oxide, and chitosan from aqueous solutions
Abstract
We determined the character of interactions between calcium hydroxyapatite Са10(РO4)6(ОН)2 (HA), graphene oxide (GO), and chitosan (С6Н11NO4)n (CHT) to yield HA/CHT/GO nanocomposites (NCs) in the СаС12–(NH4)2НРО4–NH3–Н2О–(С6Н11NO4)n–GO system (25°С). A set of physicochemical methods helped us to elucidate composition–synthesis parameters–structure–particle size–properties correlations for the prepared NCs and to prove the feasibility to manufacture NCs with tailored HA, CHT, and GO contents, described by the bulk formula Са10(РО4)6(ОН)2 · х(С6Н11NO4)n · yGO · zН2О, where х = 0.1, 0.2, 0.3; y = 0.6, 1.2, 2.4; and z = 6.0–7.4.



Stabilizing the associated non-autonomous phase upon thermal expansion of Zn2V2O7
Abstract
The previously unknown effect of emergence of an associated non-autonomous phase upon heating of zinc pyrovanadate Zn2V2O7 within the region of negative volume expansion is detected. Comparison of the data of high-temperature X-ray diffraction of the Zn2V2O7 samples synthesized via solution and solid-phase routes shows that the grain size affects the stabilization of the non-autonomous phase. The presence of a non-autonomous phase results in self-dispersion of the substance upon phase transition in heating–cooling cycles.



Synthesis of [(H3O)Tm3F10] · nH2O, ErF3, and TmF3 powders and their physicochemical properties
Abstract
Reaction of Er2S3 powder with aqueous HF solution (49%) followed by drying of the resultant precipitate at 25–95°C has afforded X-ray amorphous phase preferably as ErF3 · 0.87H2O hydrate. The resultant phase have been shown to undergo thermal dissociation at 50–165°C (ΔH = 97.8 J/g, Δm = 5.5 wt %), Δm is 1 wt % in temperature range 165–270°C. Exothermal effect at 236–270°C (ΔH =–64.3 J/g) has correlated with formation of polycrystalline compound ErF3: space group Pnma, a = 0.634(8) nm, b = 0.684(2) nm, c = 0.438(2) nm. The size of particles of ErF3 phase formed at 170°C calculated by the Selyakov–Scherrer formula has been found to be 45 × 60 nm. The reaction of Tm2S3 with HF solution at 25°C has led to a phase of composition [(H3O)Tm3F10] · 1.7H2O: space group Fd3-m, a = 1.5389(5) nm whose particles are regular octahedra in shape and 4–8 μm in size. Upon heating of the prepared compound to 150°C (ΔH = 51.1 J/g, Δm = 4.2 wt %), water molecules go to gas phase, while crystal structure of the phase retains: a = 1.5353(3) nm. Three-quarter of water molecules nave been lost in temperature range 150–225°C (ΔH = 23.4 J/g, Δm = 3.8 wt %). Exothermal effect at 225–270°C (ΔH =–18.8 J/g) has been accompanied by formation of polycrystalline structure of compound TmF3: space group Pnma, a = 0.627(8) nm, b = 0.681(3) nm, c = 0.440(9) nm. Particles of compound TmF3 have been found to be 110–250 nm in size.



Coordination Compounds
Synthesis and luminescent properties of copper(I) complexes with 3-pyridin-2-yl-5-(4-R-phenyl)-1H-1,2,4-triazoles
Abstract
A series of heteroligand copper(I) complexes with 3-pyridin-2-yl-5-(4-R-phenyl)-1H-1,2,4-triazoles (R = H, CH3, CH3O) and PPh3 of general composition CuIL(PPh3) have been synthesized and studied. The compounds have been characterized by elemental analysis, IR spectroscopy, and diffusion reflectance spectra. The structure of the complex with 3-pyridin-2-yl-5-phenyl-1H-1,2,4-triazole has been determined by single-crystal X-ray diffraction analysis. The complex is mononuclear and has a tetrahedral environment of the central atom. The compounds exhibit strong visible photoluminescence (λmax = 599–609 nm). Quantum-chemical calculations at the B3LYP/DGDZVP level have demonstrated that the short phosphorescence life-time of the CuIL(PPh3) compounds is caused by intensity transfer from the S0–S2 transition through spinorbit coupling induced by the rotation of the iodine 5p orbital upon the T1–S2 transition.



Complex-forming and ion-selective properties of bis(2-diphenylphosphorylalkyl)phenyl ethers of ethylene glycols. Crystal structures of cadmium complexes
Abstract
New complexes of cadmium iodide with 1,3-bis[2-(diphenylphosphoryl)phenoxy]propane [CdL0I2], 1,2-bis[2-(diphenylphosphorylethyl)phenoxy]ethane [CdL1, 2I2], and 1,8-bis[2-(diphenylphosphorylethyl) phenoxy]-3,6-dioxaoctane [CdL3, 2I2] are synthesized and their IR spectra and crystal structures are studied. Electroanalytical characteristics of membranes of ion-selective electrodes based on L0, L1, 2, L3, 2, and known crown ethers are compared for cations of alkali, alkaline-earth, and transition metals. Ligand L3, 2 is the first podand with terminal diphenylphosphoryl fragments to exhibit selectivity with respect to the cadmium cation.



Two supramolecular complexes based on 4-hydroxybenzoic acid and triethanolamine: Synthesis and structure
Abstract
Two new copper and nickel complexes with triethanolamine (TEA) and 4-hydroxybenzoic acid (L) have been synthesized within the framework of systematic studies into the formation of mixed-ligand metal complexes on the basis of commercially available compounds with the simplest structure, such as ethanolamines and benzoic acid monoderivatives (hydroxy-, amino-, and nitrobenzoic acids). According to X-ray diffraction data, the complexes have the compositions [Cu2(L)2(TEA)2] · [Cu(TEA)2] · 2H2O (I) and [Ni(TEA)2] · 2L (II). Compound I is a mixed-ligand complex, while complex II is a supramolecular compound consisting of a nickel–TEA monoligand complex anion and non-coordinated L. TEA molecules in complex I are coordinated in both tetradentate and tridentate mode, while only tridentate coordination is typical for complex II. The coordination polyhedra of metal atoms are tetragonal bipyramids elongated due to the Jahn–Teller effect in complex I and octahedra in complex II. In both crystals, structural units are linked into 2D associates via hydrogen bonds.



Theoretical Inorganic Chemistry
Formation and structure specifics of the SnCl4 complex with pyridine-3-carboxylic acid chloride by ab initio calculations
Abstract
Feasible structures of the SnCl4 complex with pyridine-3-carboxylic acid chloride were calculated by the MP2/LANL2DZ method. The results of calculations were compared to experimental 35Сl nuclear quadrupole resonance (NQR) data. The coordination site of the ligand was found to be the nitrogen atom and not the carbonyl oxygen atom. The partial negative charge of the electron-donating center and the positive charge of the electron-drawing center increase appreciably upon complex formation.



Molecular structures of macrotricyclic 4d M(II) chelates with the (NNNN)-donor ligand 2,7-dithio-3,6-diazaoctadiene-3,5-dithioamide-1,8 according to quantum-chemical density functional theory calculations
Abstract
The thermodynamic and geometric parameters of the molecular structures of macrotricyclic Mo(II), Ru(II), Rh(II), Pd(II), Ag(II), and Cd(II) complexes with the tetradentate ligand 2,7-dithio-3,6-diazaoctadiene-3,5-dithioamide-1,8 with the (NNNN) coordination of the donor centers have been calculated by the hybrid density functional theory (DFT) method in the OPBE/TZVPQZP approximation with the use of the Gaussian09 program package. The Pd(II), Ag(II), and Cd(II) complexes are exactly planar, the Tc(II) and Rh(II) complexes exhibit slight deviations from coplanarity, while the Mo(II) and Ru(II) complexes have rather significant deviations. The five-membered chelate rings in the complexes are either strictly planar or deviate slightly (no more than by 5°) from coplanarity.



Coordination of ions in aqueous solutions of samarium chloride from X-ray diffraction data
Abstract
The radial distribution functions for aqueous solutions of samarium chloride over a broad concentration range under standard conditions, obtained previously by X-ray diffraction, were used to develop various physically substantiated models for structural organization of the systems. The optimal versions were identified by calculating the theoretical functions for each model and comparing their agreement with experimental functions. The quantitative characteristics of the local environment of Sm3+ and Cl– ions such as coordination numbers, interparticle distances, and sorts of ion pairs were established. The average number of water molecules in the first coordination sphere of the cation was found to decrease from 9 to 6 with increasing concentration. The structure of the systems is determined by solvent-separated ion associates over the whole concentration range.



Structural-dynamic properties of infinitely dilute ionic liquid–nonpolar compound systems
Abstract
The effect of nonpolar solvents (argon, methane, and benzene) on the structural-dynamic properties of an ionic liquid (IL), dimethylimidazolium chloride, is studied at 400 K by the method of molecular dynamics using DL_POLY _4.05 software package. The energy and structural-dynamic parameters of infinitely dilute liquid ternary systems are calculated and analyzed. The pattern of motion of the molecules of dilute compound in the IL is described. It is demonstrated that increased size of a solvent molecule enhances the effect on the ionic liquid structure, which also influences the solubility of nonpolar compounds and IL.



Physical Methods of Investigation
Hydrolysis of nitrilium derivatives of the closo-decaborate anion [2-B10H9(N≡CR)]– (R = CH3, C2H5, C(CH3)3, or C6H5)
Abstract
Reaction of tetrabutylammonium salts of [2-B10H9(N≡CR)]– (R = CH3, C2H5, C(CH3)3, or C6H5) anions with water results in N-borylated iminols (Bu4N)[2-B10H9NH=C(OH)R], and in the presence of an alkali, corresponding N-substituted amides (Bu4N)2[2-B10H9NH-C(=O)R] are formed. The compounds obtained are identified by IR, ESI/MS, and 1H, 11B, and 13C NMR spectroscopy. The crystal structure of compound (Bu4N)[2-B10H9(Z-{NHC(OH)C2H5})] is studied by X-ray diffraction.



Intermolecular interactions and spin states of complexes [Fe(3-MeO-Qsal)2]Y (Y = PF6, BF4)
Abstract
Compounds [Fe(3-MeO-Qsal)2]Y (Y = PF6, BF4) have been prepared by diffusion method and studied in temperature range 5–300 K by EPR and magnetic susceptibility methods. The coexistence of spatially separated high-spin (solvated) and low-spin (unsolvated) fractions in the studied compounds has been established. It has been shown that change in the type of outer-sphere anion leads to change in the character of intermolecular interactions in the high-spin fraction and has no effect on the parameters and character of interactions of paramagnetic centers in the low-spin fraction.



Features of thermophotoinitiated degradation of nanocluster polyoxomolybdate Mo132 and its polymer-containing composites
Abstract
An EPR spectroscopy study was made into the simultaneous effect of intense degradation factors (UV radiation, elevated temperature) on nanocluster porous polyoxomolybdate Mo132 of the Keplerate type in the solid state and also into the behavior of film composites including water-soluble nonionogenic polymers (polyvinylpyrrolidone, polyethylene glycol) under the action of these factors. The effect of mutual stabilization of polyoxometalate and polymer components in the studied composites was detected.



Thermal studies of potassium tetrahydroborate−sodium tetrafluoroborate mixtures
Abstract
The KBH4−NaBF4 mixture was studied by thermal analysis (differential scanning calorimetry). Chemical analysis, X-ray powder diffraction analysis, IR spectroscopy, and 11B and 19F MAS NMR spectroscopy showed that the primary stage of the complex pyrolysis process is a metathesis reaction between components to form a new mixture, NaBH4−KBF4, the decomposition of which with the release of gaseous products and the formation of polyhedral borohydride compounds (mainly B12H122-) in the solid residue begins at a temperature of about 563 K. At a certain ratio between reactants in the initial mixture KBH4−NaBF4, the B12H122- anion can form with the material participation of the BF4- anion.



Neutron diffraction study of dehydrogenation of titanium carbohydrides TiCxHy
Abstract
The possibility of the synthesis of hydrogen-nonstoichiometric cubic titanium carbide ТiСх of high purity from powdery nonstoichiometric cubic titanium carbohydride ТiСхHy or nonstoichiometric titanium carbide with admixture hydrogen by annealing in a continuously maintained vacuum of no worse than 1.33 × 10–3 Pa at temperatures of 600–750°C for several hours has been shown. Similar annealing at higher temperatures (T ≥ 800°C) does not lead to the complete removal of hydrogen from a sample due to intensive sintering. In this case, it seems that pores between sintered particles are hydrogen traps, and the release of hydrogen through the surface of sintered particles is hindered.



Physicochemical Analysis of Inorganic Systems
Modeling of the composition of the eutonic solution in the NaCl–AlCl3−SrCl2–HCl–H2O system at 25°С and its experimental confirmation
Abstract
The solubility was studied in the system NaCl–AlCl3−SrCl2–HCl–H2O of the eutonic type at 25°C in the section 28 wt % HCl. It was determined that it is possible to derive equations of the solubility surface of crystallizing salts and to calculate the composition of the eutonic solution.



Physical Chemistry of Solutions
Reaction of μ-carbido-dimeric iron(IV) octapropyltetraazaporphyrinate with dicumene peroxide and tert-butyl peroxide in benzene
Abstract
We report the results of our studies into the oxidation reactions of μ-carbido-dimeric iron(IV) octapropyltetraazaporphyrinate with organic peroxides. Kinetic parameters have been determined, and a possible scheme of the process suggested. The nature of peroxide has been shown to influence the rates of redox transformations. The reaction has been shown to generate the μ-carbido-dimeric iron(IV) octapropyltetraazaporphyrinate radical cation through the dissociation of the О–О bond in the peroxide coordinated to the iron atom. The reaction product enters an aggregated state over time, and readily recovers the initial form in the presence of a nitrogen-containing base.



Magnesium(II) and cadmium(II) octaphenyltetraazaporphyrinates in metal exchange reaction with MnCl2 in DMSO
Abstract
Reaction kinetics of metal exchange of Mg(II) and Cd(II) octaphenyltetraazaporphynates with MnCl2 in DMSO has been studied by spectrophotometry. Kinetic parameters of the metal exchange reaction have been determined. Possible stoichiometric reaction mechanism has been suggested. Effect of solvent and salt solvate nature on the rate of metal exchange reaction has been revealed.



Association of bromate ion in nonaqueous solutions of alkali metal salts
Abstract
Manifestations of ion association of lithium cation with BrO3- ion in the vibrational spectrum have been studied by IR spectroscopy. The microstructure of the bromate ion with lithium cation in a contact ion pair in an aprotic solvent has been determined by the density functional theory method in the B3LYP/cc-pVTZ approximation, and the vibrational spectrum of coordinated bromate ion has been calculated.



Development of a rapid and reliable liquid-liquid extractive method for the effective removal of chromium(VI) from electroplating waste water and tannery effluents
Abstract
A rapid and selective liquid-liquid extractive system is developed for extraction of Cr(VI) by employing N-n-OCA reagent and xylene as solvent. Quantitative extraction of Cr(VI) is observed in the concentration range of 0.4 to 0.7 M HCl. The extracted [Cr(VI)-N-n-OCA] complex from the organic phase was back extracted by 6.0 M ammonia (3 × 10 mL) and spectrophotometrically quantified. Various parameters were explored to study their influence on quantitative extraction of Cr(VI) by varying N-n-OCA concentration, equilibration time, effect of diluents, acid concentration and diverse ions. Stoichiometry of the extracted complex showed 1: 1 ratio of acid and amine. The relative standard deviation of the developed method is 0.09 with respect to calibration range 0.2 to 0.8 μg mL–1. The validity of the proposed method was checked by applying it to the associated and toxic metals in binary, synthetic mixtures and ternary effluents.


