Search

The complexes [Co(NH3)6][Ir(C2O4)3] and [Ir(NH3)6][Co(C2O4)3]·H2O have previously been synthesized and their thermal properties studied. The [Ir(NH3)6][Ir(C2O4)3] and [Co(NH3)6][Co(C2O4)3]·3H2O complexes considered here are the end members in a series of possible isostructural solid solutions based on the complex salts in the Co–Ir system. Their crystal structures and thermal properties are described in detail, including temperature-dependent in situ X-ray diffraction. During the thermolysis of these compounds, layered metal nanoparticles are formed. Close attention is paid to the details of the [Co(NH3)6][Ir(C2O4)3] synthesis. It has been shown that the formation of this complex salt is temperature dependent; upon heating, a new phase of the K3[Co(NH3)6][Ir(C2O4)3]2·6H2O salt is formed, which incorporates the initial iridium compound into the crystal structure of the double complex salt. The target [Co(NH3)6][Ir(C2O4)3] product is obtained if the synthesis is carried out at room temperature.

New coordination compounds trans-bis(oxalato)diaquarhodiate sodium dihydrate Na[Rh(H2O)2Ox2]·2H2O (crystallizes in two polymorphic forms NaRh-1 and NaRh-2), trans-bis(oxalato)hydroxoaquarhodiate sodium tetrahydrate Na2[Rh(H2O)(OH)Ox2]·4H2O (Na2Rh) and trans-bis(oxalato)diaquarhodic acid tetrahydrate (H3O)[Rh(H2O)2Ox2]·4H2O (HRh) are synthesized. The compounds are characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction. NaRh-1, NaRh-2 and Na2Rh crystallize in space group P 1. Trans-bis(oxalato)diaquarhodic acid exists not only in solution, but can also crystallize as a tetrahydrate (space group C2/c). The formation of various species in solution of rhodium hydroxide in oxalic acid and their redistribution were studied using 103Rh NMR spectroscopy.

The following salts have been synthesized and structurally characterized: Na2[IrF6]·2H2O (C2/m, a = 6.6327(4), b = 10.0740(6), c = 5.9283(5) A, β = 122.3880(10)°) and Na3[IrF6]·2H2O (R-3, a = 7.5963(3), b = 7.5963(3), c = 9.8056(4) A) (for the first time) by single-crystal X-ray diffraction; the unit cell parameters of a tetragonal phase (P42/mnm, a = 5.005(2), c = 10.074(4) A) of the stable α-Na2[IrF6] were determined for the first time; and the unit cell parameters of β-Na2[IrF6] (P321, a = 9.332(4), c = 5.136(2) A) and Na3[IrF6] (P21/n, a = 5.567(4), b = 5.778(4), c = 8.017(2) A, β = 90.41(2)°) were determined using powder X-ray diffraction (PXRD). The data of the thermal stability was obtained by differential thermal analysis (DTA) for all substances. The presence of Na3[IrF6]·H2O monohydrate is predicted. H2[IrF6] was prepared in a solution and was demonstrated to behave as a strong dibasic acid.

The transformations of Pt complex species in concentrated NaOH solutions (1-12 M) of Na

The single-source precursors of noble–ignoble nanoalloys are of a great interest since they can be used in many areas such as optical, biomedical, catalysis, magnetic and chemosensors. The new water-soluble double complex salts (DCSs) with aqua and oxalato ligands, [M(H2O)6][Pd(Ox)2]·nH2O (M = Co2+, Ni2+; n = 2, 4; Ox = C2O 4 2− ), were obtained, structurally characterized (single-crystal XRD) and used as precursors for M–Pd nanoalloys. Complexes, intermediate and final thermolysis products were studied by simultaneous thermogravimetric analysis combined with mass spectrometry, powder XRD, in situ synchrotron powder XRD, IR and X-ray photoelectron spectroscopy. Decomposition in different atmospheres leads to formation of bimetallic solid solution M0.5Pd0.5 (He, H2) or a mixture of metal oxides (O2). The catalysts M–Pd/TiO2 (1% Pd) were prepared by the decomposition of DCSs deposited onto titania via wetness impregnation. The H2-made Ni-containing samples showed a high photocatalytic activity in CO oxidation reaction.

A series of tetraalkylammonium salts with anionic platinum nitrato complexes (Me4N)2[Pt2(μ-OH)2(NO3)8] (1), (Et4N)2[Pt2(μ-OH)2(NO3)8] (2), (n-Pr4N)2[Pt2(μ-OH)2(NO3)8] (3b), (n-Pr4N)2[Pt(NO3)6] (3a)...

The thermal behaviour of Ag2[PtCl4] and Ag2[PtCl6] complex salts in inert and reducing atmospheres has been studied. The thermolysis of compounds in a helium atmosphere is shown to occur in two stages. At the first stage, the complexes decompose in the temperature range of 350-500°C with the formation of platinum and silver chloride and the release of chlorine gas. At the second stage, silver chloride is sublimated in the temperature range of 700-900 °C, while metallic platinum remains in the solid phase. In contrast to the thermolysis of Ag2[PtCl6], the thermal decomposition of Ag2[PtCl4] at 350 °C is accompanied by significant heat release, which is associated with disproportionation of the initial salt to Ag2[PtCl6], silver chloride, and platinum metal. It is confirmed by DSC measurements, DFT calculations of a suggested reaction, and XRD. The thermolysis of Ag2[PtCl6] and Ag2[PtCl6] compounds is established to occur in a hydrogen atmosphere in two poorly separable steps. The compounds are decomposed within 170-350°C, and silver and platinum are reduced to a metallic state, while a metastable single-phase solid solution of Ag0.67Pt0.33 is formed. The catalytic activity of the resulting nanoalloy Ag0.67Pt0.33 is studied in the reaction of CO total (TOX) and preferential (PROX) oxidation. Ag0.67Pt0.33 advanced Pt nanopowder in activity in CO TOX, but was not selective in CO PROX.

The article describes the synthesis of composite sorbents by immobilizing iron oxide in a polymer matrix with subsequent hydrothermal treatment at a temperature of 175 &deg, C. The sorbents based on magnetite and hematite were synthesized, their magnetic properties and phase composition were evaluated, and the iron content was determined. Sorption characteristics of the composites towards microconcentrations of Sr-90 radionuclide in solutions with different mineralization and pH were investigated. It was shown that the sorbent based on magnetite was the most efficient. In alkaline media with pH above 11, the composite sorbent based on magnetite exhibited increased selectivity towards Sr-90 and proved to be suitable for application under dynamic sorption conditions with subsequent desorption of the radionuclide with a solution of HNO3.

The thermal behavior of double complex compounds (DCC) [Cr(ur)6][Co(CN)6]·4H2O (I), [Cr(ur)6][Co(C2O4)3]·3.5H2O (II), [Cr(ur)6][Fe(CN)6]·4H2O (III), [Cr(ur)6][Fe(C2O4)3]·2H2O (IV) and urea (ur) was studied (ur = urea, H2NCONH2). Thermal decomposition was carried out by the TG-MS method and method of static experiments in the reducing atmosphere at a 1-h exposure. The final thermolysis products are characterized by elemental analysis, XDR, IR spectrometry, SEM, the specific surface area (SBET) of the samples. The porous structure of the samples was determined. Cr2O3 + Co0 are formed as a result of thermal reduction of I, II, Cr2O3 + Fe0 + Fe2O3 for III, FeCr2O4 + Fe0 for IV. The replacement of CN− ligands by C2O42− ligands leads to an increase in the specific surface by a factor of ~ 2. Catalytically activity of Co-containing degradation products is demonstrated in the model catalytic decomposition of H2O2. The relationship between SBET and the obtained values of the rate constants of the reaction is not observed. Fe-containing samples are not catalytically active.

The thermal behavior of double-complex salts [Cr(ur)6][Fe(CN)6]·4H2O (I), [Cr(ur)6][Co(CN)6]·4H2O (II), [Cr(ur)6][Fe(C2O4)3]·2H2O (III), [Cr(ur)6][Co(C2O4)3]·3.5H2O (IV) was studied (ur = urea, H2NCONH2). Thermal decomposition was carried out by the method of static experiments in an oxidizing (air) atmosphere at a 1-h exposure. The products of thermolysis were characterized by the X-ray diffraction method. The porous structure and the specific surface of the samples were determined. For Cr–Co systems at temperatures above 600 °C, the formation of a single-phase spinel of the composition Co1.5Cr1.5O4 was recorded, whereas for the Cr–Fe systems the formation of a mixed oxide phase (Fe,Cr)2O3 occurred with heating up to 900 °C. It was shown that in all cases, as the temperature increased, the specific surface area decreased and the calculated particle size of the oxidation products increased. Thermolysis products were investigated in the model reaction of catalytic oxidation of acetone with air oxygen. The obtained values of the rate constants of the reaction show that the replacement of Fe with Co does not significantly affect the catalytic activity of the products, and only an increase in the temperature of thermolysis leads to a certain decrease in the catalytic activity.

Three new zinc three-dimensional coordination polymers with flexible 1,3-bis(1,2,4-triazol-1-yl)propane ligand were synthesized. The crystal structures of synthesized compounds were determined, and structural peculiarities are discussed. Coordination compounds with composition [Zn(btrp)(bdc)]·nDMF are interpenetrated frameworks, while metal–organic framework (MOF) [Zn3(btrp)(bdc)3]·nDMF is not. Thermal stability and luminescent properties of synthesized compounds have been investigated. The possibility of usage of such compounds as sensitive materials for some aromatic compounds are explored, and it was shown that luminescence of coordination polymers is completely quenched in the presence of nitrobenzene. Sorption properties of synthesized MOFs toward nitrogen, carbon dioxide, and hydrogen were evaluated.

X-ray diffraction (XRD) pattern of nanosized equimolar solid solution CoIr prepared by thermolysis of [Co(NH3)6][Ir(C2O4)3] contains peaks characteristic of both face-centered cubic (fcc) and hexagonal close-packed (hcp) structure. Moreover, 101 peak of hcp modification is substantially wider than 100 and 002 peaks, 102 and 103 are very broad and almost invisible. Peak 200 of fcc structure is wider than the other peaks of this modification and slightly shifted toward lower angles. It was shown by simulation of XRD patterns that particles of CoIr alloy are nanoheterogeneous and consist of lamellar domains having fcc and hcp structures. The best fit was obtained for the following model parameters: an average crystallites size is about 10 nm, average thicknesses of the fcc and hcp domains are 1.7 and 1.1 respectively. The presence of domain structure was confirmed by transmission electron microscopy data.

An exchange reaction between Ba[RuNO(NO2)4OH] and cobalt (nickel) sulphate results in the formation of heterometallic [RuNO(NO2)4OHM(H2O)3] complexes with bridging (N,O)-NO2 and μ-(OH) ligands. The crystal structures of both complexes are determined. Thermal decomposition in H2/He atmosphere leads to the formation of solid solutions of the metals. In the case of the nickel complex, the compositions of the prepared solid solutions are in the miscibility gap. In oxygen atmosphere mixed oxide systems NiO–RuO2 and Co3O4–RuO2 are formed in temperature interval from 400 to 600 °C. At temperatures from 900 to 1000 °C spinel-type phase Co2.1Ru0.9O4 is formed.

[M(NH3 )4 ]A (M=Pt, Pd; A=CrO4 , Cr2 O7 ) and [Pt(NH3 )4 (NO2 )(Cr2 O7 )]NO3 complex salts were synthesized and characterized by a number of physicochemical methods of analysis (IR, single-crystal and powder XRD, and simultaneous thermogravimetry and differential scanning calorimetry with evolved gas analysis mass spectrometry). Thermolysis of the salts obtained in a hydrogen atmosphere proceeds with the partial reduction of chromium to a metallic state and the formation of Mx Cr1-x (M=Pt, Pd) metal solid solution with a chromium content of up to 22 at % and chromium(III) oxide. The thermal decomposition of salts in an inert and oxidizing atmosphere passes through the formation stage of the MCrO2 phase with the delafossite structure followed by its subsequent decomposition into chromium(III) oxide and noble metal. Nanosized Pt-Cr2 O3 and Pd-Cr2 O3 composites obtained by the thermolysis of precursor salts in air at 500 °C and being held at this temperature for 1 h showed a high catalytic activity in the CO total oxidation (TOX) and preferential oxidation in the excess of hydrogen (PROX) processes compared with that of monometallic Pt and Pd powders.

For the first time, orthogonally substituted azole-carboxylate adamantane ligands were synthesized and used for preparation of coordination polymers. The angle-shaped ligands were prepared by the reaction of 1-adamantanecarboxylic acid and azoles (1H-1,2,4-triazole, 3-methyl-1H-1,2,4-triazole, 3,5-dimethyl-1H-1,2,4-triazole, 1H-tetrazole, 5-methyl-1H-tetrazole) in concentrated sulfuric acid. Variation of the solvent and substituents in azole rings allowed to prepare both 1D and 2D copper(II) and nickel(II) coordination polymers, [Cu2(trzadc)4(H2O)0.7]∙DMF∙0.3H2O, [Cu(trzadc)2(MeOH)]∙MeOH, [Ni(trzadc)2(MeOH)2] and [Cu2(mtrzadc)3(MeOH)]+NO3&ndash, (trzadc-3-(1,2,4-triazol-1-yl)-adamantane-1-carboxylic acid, mtrzadc-3-(3-methyl-1,2,4-triazol-1-yl)-adamantane-1-carboxylic acid) which were structurally characterized by single crystal X-ray diffraction. Complex [Cu(trzadc)2(MeOH)]∙MeOH was shown to act as a catalyst in the Chan-Evans-Lam arylation reaction.

Two binuclear coordination compounds of Cu(II) chloride with the bitopic ligand 1,1,2,2-tetrakis(pyrazol-1-yl)ethane (Pz4) of the composition [Cu2(&micro, 2Pz4)(DMSO)2Cl4]&middot, 4H2O and [Cu2(&micro, 2Pz4)(DMSO)2Cl4]∙2DMSO were prepared and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction, and powder diffraction analysis. It was shown that in contrast to silver(I) and copper(II) nitrates, copper(II) chloride forms discrete complexes instead of coordination polymers. The supramolecular structure of the complex [Cu2(&micro, 4H2O with lattice water molecules is formed by OH&middot, &middot, Cl and OH&middot, O hydrogen bonds. Density functional theory (DFT) calculations of vibrational frequencies of the ligand and its copper(II) complex allowed for assigning IR bands to specific vibrations.

The structures of K3[Ir(C2O4)3]·0.5KCl·4H2O and K3[Ir(C2O4)3]·4.25H2O were determined by single-crystal X-ray diffraction. Thermal transformations of the compounds were studied by several physical methods. Single-step coordination sphere decomposition followed by formation of Ir and CO2 was shown. It is found that the redox process with CO2 release passes easier for K3[Ir(C2O4)3]·0.5KCl compound than for K3[Ir(C2O4)3] one.

Three new double complex salts (DCSs) containing [Pt(NO3)6]2- anion and Rh(III) metalorganic cations [Rh(4-pic)4Cl2]2[Pt(NO3)6] (1,4-pic = 4-methylpyridine), [Rh(bpy)3]2[Pt(NO3)6]3 (2, bpy = 2,2′-bipyridiine) and [Rh(bpy)3][Pt(NO3)6](NO3)(CH3COCH3)(CH3CN)(H2O) (3) were prepared and characterised by elemental analysis and infrared spectroscopy. Crystal structures of 1 and 3 were determined using X-ray single crystal analysis. Thermal decomposition of salts 1 and 2 in various atmospheres (He, He/H2, air) was shown to yield Rh–Pt solid solutions with a Rh:Pt ratio inherited from the starting salt composition. The Rh0·67Pt0·33/CeO2 catalyst was prepared by thermal decomposition of salt 1 supported on a CeO2 surface. The catalyst was tested in a CO oxidation reaction and demonstrated full conversion of CO from about 145 °C at gas hourly space velocity of 200 000 ml g−1 h−1.

Reaction between 1,1,2,2-tetra(pyrazol-1-yl)ethane (Pz4) and copper(II) nitrate in ethanol at room temperature and in solvothermal conditions (90 °C) lead to coordination polymers of two different structures. A ribbon-like coordination polymer {Cu2(μ2-NO3)2(H2O)4 μ′2-Pz4}n was formed at room temperature in which nitrate ions bind the monomeric units, while Pz4 ligands are responsible for cross-linking of {Cu(μ-NO3)} chains. At 90 °C linear 1D coordination polymer was formed, in which Pz4 ligands bridge copper ions that in addition bear two monodentate nitrate ions.

Factor analysis is the basic tool when conducting a comprehensive analysis of economic activity. In the factor analysis, the major attention is given to the research of internal reasons that form the specificity of the phenomenon under study and identification of generalized factors standing behind relevant specific indicators. The article deals with the analysis of the science intensity of the invested capital in the Baikal region of the Russian Federation. Science intensity is an important parameter for determining the efficiency of the economic activity. The author introduced into scientific circulation the following indicators: the science intensity of the invested capital, the science intensity of the gross regional product and the investment return of the gross regional product. The paper reveals the influence of factors affecting the change in the science intensity of the invested capital in the Baikal region of the Russian Federation, and provides methodological approaches to its calculation. The article presents the author’s analytical and systematized statistical material for the analysis of the key indicators revealing the impact of the invested capital in the Baikal region of the Russian Federation on the change of the science intensity. The research has been carried out in the framework of the scientific project of the Irkutsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences No. XI.174.1.4 “Activation of the internal development potential of regions of the resource specialization (on the example of the Baikal region)”.

Rhodium(III) hydroxide was shown previously to possess the catalytic activity in the rearrangement reaction of primary oximes to amides. Alkaline solutions of rhodium(III) chlorocomplexes are routinely used for Rh(OH)3 preparation and allow for a diversity of rhodium hydroxocomplexes that hold a wide range of catalytic properties. In this study, two Al2O3 supported catalysts containing 1) exclusively [Rh(OH)6]3− species and 2) a mixture of rhodium hydroxocomplexes with one to four rhodium atoms ([Rh(OH)6]3–, [Rh2(μ−OH)2(OH)8]4–, [Rh3(μ−OH)3(OH)12]6–, [Rh4(μ−OH)6(OH)12]6) were prepared, characterised (XRD, Raman, EXAFS) and tested in the benzaldoxime to benzamide rearrangement. The catalyst containing polynuclear complexes possessed at least three times higher turnover frequency (TOF) and better selectivity than the [Rh(OH)6]3– based catalyst. According to the EXAFS data, the reduction of rhodium(III) took place under reaction conditions yielding small rhodium clusters (CNRh-Rh = 4), which were proposed to be the active sites of catalysts.

All the steps of the proposed technique, from the synthesis of single-source precursors to the preparation of CoPd and CoPt nanoalloys, are described. The double complex salts (DCS) [M(NH3)4][Co(C2O4)2(H2O)2]·2H2O (M = Pd, Pt), which were synthesized by mixing solutions containing [M(NH3)4]2+ cations and [Co(C2O4)2(H2O)2]2− anions, have been used as precursors. The salts obtained were characterized by IR spectroscopy, thermal analysis, XRD and single crystal X-ray diffraction. The prepared compounds crystallize in the monoclinic (space group I2/m, M = Pd) and orthorhombic (space group I222, M = Pt) crystal systems. Thermal decomposition of the salts in helium or hydrogen atmosphere at 200–600 °C results in the formation of nanoalloys powders (random solid solution Co0.50Pd0.50 and chemically ordered CoPt). The size of the bimetallic particles varied from 5 to 20 nm. Order–disorder structural transformations in Co0.50Pt0.50 nanoalloys were studied. The magnetic properties of both chemically disordered Co0.50Pd0.50 and ordered CoPt clusters have also been measured.

We have determined that X-ray fluorescence (XRF) spectrometry can be used as a rapid and precise method for quantitative elemental analysis of macro and micro nutrients in dairy manure. The elements chosen for this study were N, P, K, Ca, Mg, S, Zn, Mn, Fe, Cu, Al, Na, B, and C. The wavelength-dispersive XRF spectrometer was calibrated by comparing its results with a panel of dried dairy manure samples with analyses from inductively coupled plasma (ICP) obtained from three independent certified laboratories. In addition, the XRF results for C, N, and S were compared with those from a high-temperature combustion (HTC) analyzer dedicated to measurements of these three elements. Then the performance of the calibrated XRF was tested against a separate panel of dairy manure samples collected at fifteen different sampling points at a manure processing plant. Subsamples from these samples were analyzed for the 14 elements of interest by a certified laboratory. The close agreement between the XRF results and those of the certified laboratory established that XRF can be used as a simple and precise method for the elemental analysis of dairy manure

Each effective indicator depends on numerous and various factors. The more detailed is the study of the influence of factors on the magnitude of the effective indicator, the more accurate are the results of the analysis and the evaluation of the quality of the subject of the research work. Hence, in the analysis of economic activity, an important methodological issue is the study and measurement of the influence of factors on the magnitude of the economic indicators studied. The article deals with the analysis of the investment intensity of the gross regional product of the Baikal region of the Russian Federation. The author has introduced into scientific circulation the following indicators: the investment intensity of the gross regional product, the science intensity of the gross regional product and the science return of the invested capital. The paper reveals the influence of the factors affecting the investment intensity of the gross regional product in the Baikal region of the Russian Federation and provides methodological approaches to its calculation. Also, the article presents the author’s analytical and systematized statistical material for the analysis of the key indicators revealing the impact on the investment intensity of the gross regional product in the Baikal region of the Russian Federation. The paper is produced in the framework of the scientific project of the Siberian Branch of the Russian Academy of Sciences No. XI.174.1.4 “Activation of the internal development potential of regions of the resource specialization (on the example of the Baikal region)”.