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  • Author or Editor: N. B. Morozova x
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Abstract

A universal (that is, actual for any reaction) interconnection between enthalpy (Δr H), entropy (Δr S), and Gibbs energy (Δr G) was applied to the analysis of the formation of saturated vapor of individual condensed (liquid and solid) substances. This allowed us to specify the conceptual and metrological sense of thermodynamic parameters available for estimation within the framework of tensimetric investigations. Proposals for the procedures of experimental data processing were made. The informativity of the approach was illustrated by the example showing the results of processing two arrays of primary data obtained using the static and the flow methods for crystal hafnium(IV) dipivaloylmethanate.

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By means of a tensimetric flow method and a static method with a silica-membrane zero gauge, the dependence of vapour pressure on temperature was obtained for tris(2,4-pentanedionato)ruthenium(III), Ru(aa)3, and tris(1,1,1-trifluoropentane-2,4-dionato)ruthenium(III), Ru(tfa)3. The thermodynamic characteristics of vaporization and sublimation of these complexes were determined. The processes of thermal decomposition of the vapour of the compounds in vacuum, hydrogen and oxygen were investigated by using mass spectrometry in the temperature range 170–550‡C for Ru(aa)3 and 150–620‡C for Ru(tfa)3. The threshold temperatures of the stability of the vapour of the complexes and the rate constants of the thermolysis processes were determined. The main gaseous products of the thermal decomposition and the dependences of their composition on the presence of hydrogen and oxygen were established.

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Journal of Thermal Analysis and Calorimetry
Authors: Kseniya V. Zherikova, Ludmila N. Zelenina, Natalia B. Morozova, and Tamara P. Chusova

Abstract

Complexes of ruthenium(III) with the following beta-diketone derivatives: 2,4-pentanedione (Ru(acac)3), 1,1,1,6,6,6-hexafluoro-2,4-pentanedione (Ru(hfac)3), and 2-methoxy-2,6-dimethyl-3,5-heptanedione (Ru(mdhd)3) were synthesized, purified, and identified by chemical analysis and melting points. By difference-scanning calorimetry (DSC) in vacuum the thermodynamic characteristics of melting processes were defined. Using the static method with quartz membrane zero-manometer, the temperature dependencies of saturated and unsaturated vapor pressure were obtained for Ru(hfac)3. The standard thermodynamic characteristics of vaporization processes enthalpy ΔH T* and entropy Δ T* were determined.

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