Heat capacity of single-phase samarium-magnesium hexaaluminate SmMgAl11O19 was measured by relaxation, adiabatic and differential scanning calorimetry in the region 2–1864 K. Thermodynamic functions were calculated based on the smoothed values of heat capacity. Possible inaccuracies in the assessment of heat capacity and entropy using the Neumann–Kopp rule in the field of low and high temperatures are shown.

The reaction of copper(II) acetate with furoic acids (2Hfur / 3Hfur) and imidazole (Im) in methanol resulted in mononuclear complexes [Cu(fur)2(Im)2(H2O)]& sdot;L (fur- = 2fur- (1, 2), 3fur- (3); L = MeCN (1)) whose structures were determined by direct single crystal X-ray analysis. It was found for the first time that copper nanoparticles immobilized on the surface of gamma-Al2O3 obtained by chemical reduction of 1, 2 and 3 (pre-deposited on the surface from solution) with sodium tetrahydroborate show high selectivity of mono-and dihydrogenation of tricyclo [5.2.1.02,6]deca-3,8-diene (dicyclopentadiene, DCPD). The catalytic activity tests show a high selectivity (97 %) of the catalyst obtained from an ethanolic solution of complex 1 in the reaction of partial hydrogenation to DHDCPD under continuous process conditions even at high conversion values (up to 96 %) and with an excess of hydrogen, whereas the catalyst obtained from an aqueous solution of complex 1 showed 98 % total hydroge-nation product (THDCPD) selectivity. The catalysts based on all the complexes 1-3 were successfully used in reactions of nitrobenzene (NB) reduction to aniline (AN) and in the reductive alkylation of nitrobenzene with isobutanol (i-BAN) 100 % yields of aniline and N-isobutylaniline were obtained at LHSV 0.16 h-1.

The temperature dependence of the heat capacity of Y2Ti2O7 and Eu2Ti2O7 with a pyrochlore structure in the temperature range of 7–1800 K has been studied. The existence of a small shallow anomaly of the heat capacity of europium titanate in the range of 10–60 K was confirmed. The thermodynamic properties (entropy, enthalpy change, and reduced Gibbs energy) were calculated. Based on the results of calculation of the Gibbs energy of formation of the titanates from oxides it was concluded that both titanates are thermodynamically stable in the high temperature region.

A sample of Yb2O3⋅2HfO2 solid solution is synthesized and characterized via X-ray diffraction, electron microscopy, and chemical analysis. Relaxation, adiabatic, and differential scanning calorimetry are used to measure the isobaric heat capacity of the sample in the range of 2.4–1807 K, and thermodynamic functions are calculated with allowance for the contribution from low-temperature transformation. The Schottky anomaly’s contribution to the heat capacity in the region of 2.4–300 K is determined.

The molar heat capacity of the solid solution Tm2O3‧2HfO2 has been determined for the first time by relaxation, adiabatic and differential scanning calorimetry, the temperature dependences of entropy and enthalpy increment in the temperature region 0–1800 K have been calculated, and the contribution to the heat capacity of the Schottky anomaly at 0–300 K has been evaluated.

The temperature stages of crystallization process for thulium titanate of pyrochlore structural type during the heating of hydroxide precursor obtained by reverse precipitation have been studied by DSC/TG, XRD, and electron microscopy. Tm2Ti2O7 has been measured in the temperature range 2–1870 K and thermodynamic functions at 0–1900 K and the Gibbs energy of formation from oxides and elements have been calculated based on smoothed heat capacity. The contribution of the Schottky anomaly at 20–320 K into heat capacity has been revealed.

The [Сu–C6F11COOAg] system has been studied by thermogravimetry, differential scanning calorimetry, and mass spectrometry methods. It has been found that a solid-phase exchange reaction to form C6F11COOCu and silver occurs in the condensed phase of the system in a temperature range of 370–445 K. It has been found that the enthalpy of this reaction is Δr H_298.15^0 = −17.5 ± 4.0 kJ/mol and the standard enthalpy of formation of a crystalline copper complex is Δf H_298.15^0 = −2769 ± 25 kJ/mol. The sublimation of the copper complex is accompanied by the transition of dimeric (C6F11COOCu)2 molecules (Δs H_T^0 = 134.4 ± 7.2 kJ/mol) and a small amount of tetrameric (C6F11COOCu)4 molecules into the gas phase. The standard enthalpy of formation of a dimer complex in the gas phase of Δf H_298.15^0 = −5404 ± 26 kJ/mol has been calculated. The possibility of occurrence of the exothermic interaction of copper perfluorocyclohexanoate with metallic copper in the condensed phase has been explored.

This work reports on the possibility of producing oxide InGaMgO4 by two-stage heat treatment of glycine-, starch- and PVA-nitrate precursors. The products formed as a result of their heating at low temperatures (≈ 90°С) were studied by powder X-ray diffraction. It was found that the powder formed from the glycine-nitrate precursor contains nanocrystalline In2O3, and drying of the polymer-nitrate compositions leads to the production of a thermally stable X-ray amorphous product. Its annealing at temperatures above 800°C allows synthesizing powder InGaMgO4 free of impurity phases. High-temperature treatment of the powder formed from the glycine-nitrate precursor also leads to the production of InGaMgO4, but does not remove the In2O3 impurity. Using scanning electron microscopy, it was found that single-phase InGaMgO4 powders synthesized from polymer-nitrate precursors have a similar grain structure but differ in grain size distribution. Presumably, this difference is due to the structural features of starch and PVA macromolecules used for the preparation of precursors. Oxide InGaMgO4 was characterized using differential scanning calorimetry, Raman and diffuse reflectance spectroscopy. The value of its band gap energy Eg was determined using the Tauc method.

The isobaric heat capacity of pyrochlore gadolinium titanate Gd2Ti2O7 is measured in the 2–1825 K range of temperatures. Thermodynamic functions (entropy, enthalpy change, reduced Gibbs energy) are calculated using consistent smoothed values of heat capacity. The Gibbs energy of the formation of Gd2Ti2O7 from oxides in the high temperature range is estimated.

The isobaric heat capacity of magnesium praseodymium hexaaluminate PrMgAl11O19 having the magnetoplumbite structure was measured by three calorimetric methods in the temperature range 2–1865 K. Reconciled and smoothed heat capacity data were used to calculate thermodynamic functions (entropy, enthalpy change, and reduced Gibbs energy) in this temperature range. A gentle heat capacity anomaly with a peak at about 8 K was found; its entropy and enthalpy were calculated. Magnetic properties of PrMgAl11O19 were studied by dynamic magnetic susceptibility measurements in the range 2–300 K. The results of magnetic measurements revealed an anomaly on the imaginary component of dynamic magnetic susceptibility, the temperature range of which matched that of the heat capacity anomaly.

The reactions of copper(ii) and zinc(ii) acetates with anions of 5-phenylfuran-2-carboxylic acid (Hphfur) and 5-nitro-1,10-phenanthroline (nphen) or 2,2′-bipyridine (2,2′-bpy) in the MeOH/MeCN system afforded mononuclear complexes of the composition [Cu(phfur)2(nphen)H2O] (1) and [Zn(phfur)2(2,2′-bpy)]•H2O (2). The structures of these complexes were determined by X-ray diffraction analysis (XRD). According to the XRD data, the copper atom in molecular complex 1 is in a distorted square-pyramidal environment (SQ(CuN2O3) = 0.68); the zinc atom in molecular complex 2, in a distorted trigonal-bipyramidal environment (SQ(ZnN2O3) = 3.87). The supramolecular level of 1 is mediated by intermolecular π–π interactions between the aromatic moieties of the ligands and represents a 3D supramolecular structure. in the structure of 2, the water molecules of crystallization are involved in intermolecular hydrogen bonds, resulting in the formation of centrosymmetric hydrogen-bonded dimers. The supramolecular level of 2 is mediated by C—H⋯O and C—H⋯π interactions. According to the simultaneous thermal analysis, complexes 1 and 2 are characterized by different types of thermal destruction. Thus, the explosophoric groups in the ligands of compound 1 are responsible for an intense exothermic effect. The results of biological assays show a certain correlation between the type of the substituted moiety in the heterocycle and the activity against the non-pathogenic Mycolicibacterium smegmatis strain.

Lutetium stannate with a pyrochlore structure was synthesized using solid state reaction. The heat capacity of polycrystalline Lu2Sn2O7 in the temperature range of 7.99–1871 K was measured by adiabatic and differential scanning calorimetry methods. Entropy, enthalpy change, and derived Gibbs energy were calculated from the smoothed heat capacity data. The Gibbs free energy of Lutetium stannate from elements was estimated, using the ΔfS°(Т) values obtained in this work and the ΔfH°(Т) values known from the literature. The temperature dependence of the cubic crystal lattice parameter and the value of the coefficient of thermal expansion in the temperature range of 300–1273 K were determined by high-temperature X-ray diffraction.

Subsolidus phase equilibria in the La2O3–(Ni/Со)O–Sb2O5 systems have been studied. A previously unknown compound La4Sb2O11 was found to exist in the La2O3–Sb2O5 system. La4Sb2O11 has been shown to decompose at 1060°C to form La3SbO7 and LaSbO4. Two ternary oxides (LaNi2SbO6 and La2NiSb2O9) have been discovered in the La2O3–NiO–Sb2O5 system. These new compounds are stable and do not undergo polymorphic transformations throughout the range of temperatures studied (25–1350°C). The existence of previously known ternary oxides, namely perovskite La3Ni2SbO9 and rosiaite LaNi1/3Sb5/3O6, has been verified. In the La2O3–CoO–Sb2O5 system, two new compounds (LaCo2SbO6 and La2CoSb2O9) have been found along with previously known perovskite La3Co2SbO9, rosiaite LaCo1/3Sb5/3O6, and rhombohedral pyrochlore La3Co2Sb3O14. These new compounds are isostructural to those found in the nickel oxide system. La2CoSb2O9, unlike its nickel analogue, decomposes at 990°C. For LaCo2SbO6, no thermal events associated with polymorphic transitions or melting have been detected on DSC curves up to 1350°C. An inspection of diffuse reflectance spectra of the newly synthesized LaNi2SbO6, La2NiSb2O9, LaCo2SbO6, and La2CoSb2O9 phases showed that the oxidation state of nickel and cobalt in them is 2+. The 1050°C isothermal sections of La2O3–(Ni/Co)O–Sb2O5 systems have been constructed.

Borate tungstates LnBWO6 (Ln = La; La0.999Nd0.001 and La0.99Gd0.01) are synthesized by the Pechini method followed by annealing of the intermediates and examined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The crystallographic parameters of the synthesized LnBWO6 are refined by powder X-ray diffraction in two crystal systems: monoclinic (space group P21) and orthorhombic (space group P222). Reversible first-order phase transitions in the synthesized LnBWO6 are detected by the DSC method, and the temperatures and enthalpies of phase transformations are determined. The doping of LnBWO6 with Nd3+ and Gd3+ ions is shown to decrease the temperature of the LT (low-temperature) → HT (high-temperature) phase transition of LaBWO6. Two independent positions of Gd in the La0.99Gd0.01BWO6 structure are determined from the experimental electron paramagnetic resonance (EPR) data.

An ethylene glycol (EG)–acetone (AC) system is studied via differential scanning calorimetry in the −140 to +40°С range of temperatures. A phase diagram is plotted over the range of concentrations. It is found that the mixtures in the system are supercooled by more than 30°C. Low-temperature melting is recorded in the region around −98°C, which corresponds to the eutectic point temperature. The devitrification of rapidly cooled samples is observed in the range of concentrations up to ~21 mol % AC, and the temperature of devitrification is determined ( T g ~ −120°C). The plotted phase diagram of the EG–AC system is compared to a water–acetone phase diagram.

Pyrochlore-type neodymium and gadolinium zirconate hafnates have been prepared and identified. The heat capacities of the prepared samples have been measured by differential scanning calorimetry in the range 310–1800 K. Temperature-dependent cubic unit cell parameters have been determined and thermal expansion coefficients assessed in the range 298–1273 K using high-temperature X-ray diffraction. The thermal diffusivity of the samples was measured by the laser flash method, and the temperature-dependent thermal conductivity was calculated taking into account the porosity of the samples.

The synthesis and identification of lanthanum and samarium zirconate–hafnates of the pyrochlore structure type have been reported. The heat capacity of the samples in the temperature range 310–1380 K was measured by the differential scanning calorimetry method. The temperature dependences of the cubic lattice parameters were determined, and the thermal expansion coefficients were evaluated in the range 298–1273 K using high-temperature X-ray powder diffraction. The thermal diffusivity of the samples was measured by the laser flash method, and the temperature dependences of the thermal conductivity were calculated considering the porosity of the samples.

Взаимодействием ацетата бария(II) и 2-фуранкарбоновой кислоты (пирослизевая, Hfur) в водно-спиртовом растворе получен координационный полимер состава [Ba5(fur)10(H2O)4]n (1). По данным РСА 1 содержит три симметрически-независимых катиона Ba2+, различающиеся способами координации fur- анионов и координационными числами. Все три атома кислорода фуроат-анионов образуют хелатные и мостиковые координационные связи с катионами, приводящие к сложно устроенному 3D-каркасу с сотоподобной структурой. Сетка катионов Ba2+ в 1, представляющая чередующиеся би- и трехъядерные линейные фрагменты, обусловливает высокую термическую стабильность по данным синхронного термического анализа (СТА). Дегидратация координированных молекул воды из состава 1 не приводит к разрушению каркаса до 400 °С.

A coordination polymer with the [Ba 5 (fur) 10 (H 2 O) 4 ] n composition ( 1 ) is prepared by the reaction of barium(II) acetate and 2-furancarboxylic acid (pyrosmucus, Hfur) in an aqueous alcoholic solution. The XRD data show that 1 contains three symmetrically independent Ba 2+ cations with different coordinations of fur – anions and different coordination numbers. All three oxygen atoms of the furoate anions are connected by chelate and bridging coordination bonds with cations to form a complex honeycomb 3D framework. The simultaneous thermal analysis (STA) shows that high thermal stability of 1 is due to the network of Ba 2+ cations formed by alternating bi- and trinuclear linear fragments. Dehydration of coordinated water molecules from the composition of 1 does not cause the framework destruction up to 400 °C.

The reaction of barium(II) acetate and 2-furoic acid (pyromucic acid, Hfur) in a water-alcohol solution gave a coordination polymer {[Ba5(fur)10(H2O)4]} n (1). According to single-crystal X-ray diffraction data, compound 1 comprises three symmetrically independent Ba2+ cations that differ in the way in which the fur– anions are coordinated and in the coordination numbers. All the three oxygen atoms of fur– anions form chelate and bridging coordination bonds with the cations to give a complex 3D framework. The honeycomb-like network of Ba2+ ions in 1 consists of alternating bi- and trinuclear linear moieties and features high thermal stability according to synchronous thermal analysis (STA). Dehydration of coordinated water molecules from 1 does not result in framework destruction up to 400 °C.