The thermodynamic properties of Ln2BaO4 (Ln = Sm, Dy, Ho)

The thermodynamic properties of the Ln₂BaO₄ phases (Ln = Dy, Ho, Sm) were studied by the electromotive force method with a fluoride electrolyte (890–1180 K), solution calorimetry in 1.07 N hydrochloric acid at 298.15 K, and differential scanning calorimetry (298–860 K). The experimental data were jointly processed, and the thermodynamic functions of the compounds over the temperature range 298–1200 K were calculated.     

α-Aminoazoles in the Synthesis of Heterocycles. Intermediates of Reaction between 3(5)-Aminopyrazoles and Trifluoroacetylacetone

Russian Journal of Organic Chemistry -     

Synthesis and thermochemical characteristics of Na2O · Al2O3 · 2.5H2O

A pure phase of monosodium aluminate hydrate Na₂O · Al₂O₃ · 2.5H₂O (MAH) is synthesized and characterized by means of XRD, IR, SEM, TGA, and DSC. The heat capacity of the compound is measured in the temperature range of ?100 to 100°C, and the thermal contributions to enthalpy and entropy are calculated. The standard entropy, enthalpy, and Gibbs energy of formation of MAH at 298 K are estimated.     

Effect of Chemisorbed Oxide Layers Modified by Nitrogen and Sulfur Atoms on the Catalytic Properties of Platinum Metal Electrodes: A Quantum-Chemical Approach

Electrocatalytic properties of platinum metal electrodes and their dependence on nitrogen- and sulfur-containing additives to electrolyte are studied by an X discrete variation method. It is shown that rhodium catalysts are the most promising, while iridium is unsuitable for the synthesis of percompounds.     

Modification of siloxane rubber with aminoethers of boric acid

A modifying effect of amino esters of boric acid on polydimethyl/methylvinyl siloxane caoutchouc and resin based on them was studied. It is shown that small amount of this type of modifying agent leads to a marked increase in viscosity of the compositions, and improved mechanical and thermal properties of the vulcanizates. With increasing the amount of the modifying agent they begin to show properties of a plasticizer.     

Intermolecular interactions in metal-containing polymers based on 2,4-toluylene diisocyanate and open-chain analogs of crown ethers

The interaction of 2,4-toluylene diisocyanate with open-chain analogs of crown ethers containing potassium alcoholate groups is studied, and the mechanism of stabilization of the formed O-polyisocyanate end units via intermolecular interactions is proposed. The electron delocalization in intermolecular cyclic structures may be responsible for electron-transfer processes in the polymers under study.     

Photochemical Behavior and Photolysis of Protonated Forms of Levofloxacin

The effect of intermolecular proton transfer on the spectral properties of levofloxacin in the ground and excited electronic states was studied. The preferred direction of possible protolytic reactions induced by UV irradiation in this compound was studied. It was found that the proton transfer processes have a considerable effect on the capability of the compound to emit light and occur on the nanosecond timescale. The photochemical reactions of the tree forms of levofloxacin (pH: 4.0, 7.0, 10.0) were studied by laser flash photolysis and product studies. Irradiation at pH 4 yielded a pulse and transient (λ_max = 395, 515, 575 nm) assigned to the protonated triplet. Irradiation at pH 7 yielded a transient species (λ_max = 525, 610 nm) assigned to the neutral form. Protonation of the anionic singlet excited state was also observed (λ_max = 440, 570, 680 nm).     

Thermodynamic properties of nitro derivatives of diphenyl ether and biphenyl

The heat capacity of 4,4′-dinitrodiphenyl ether and 4-nitro-4′-biphenylcarboxylic acid were measured by adiabatic calorimetry (AC) in temperature ranges of 8–372 K and 10–372 K, respectively. The heat capacity of 4,4′-dinitrodiphenyl ether in the temperature range 323–500 K, the thermodynamic properties of fusion, and the purity of the ether were measured by differential scanning calorimetry (DSC). The main thermodynamic functions in the temperature range 5–370 K were calculated for both compounds using the heat capacities of adiabatic calorimetry. Related thermodynamic functions of 4,4′-dinitrodiphenyl ether in the temperature range 370–500 K were calculated on the basis of DSC data.     

Thermodynamic properties of nonsuperconducting Ln2CuO4 (Ln = Nd, Sm, Eu), Ho2Cu2O5 and Ln2BaCuO5 (Ln = Nd, Sm, Eu, Ho, Yb) cuprates

Thermodynamic properties of rare-earth Ln₂CuO₄ (Ln = Nd, Sm, Eu), Ho₂Cu₂O₅ and Ln₂BaCuO₅ (Ln = Nd, Sm, Eu, Ho, Yb) cuprates were determined using the electromotive force method with a fluorine-ion electrolyte in the temperature interval of 1000–1230 K. The thermodynamic data obtained by different experimental methods were compared.     

Binuclear heterometallic {M-Ln} pivalate complexes (M = Co, Ni, Cu; Ln = Sm, Gd): synthesis, structure, and thermolysis

Binuclear heterometallic complexes (??²-bpy)CoLn(Piv)₅(H₂O), (??²-bpy)NiLn(Piv)₅(H₂O), and (??²-bpy)CuLn(Piv)₅(HPiv) (Ln = Sm or Gd, Piv- is the pivalate anion) were synthesized. A comparative study of the structural characteristics and the thermolysis of the resulting compounds was performed.