Authors:J. Selvakumar, V. Raghunathan, and K. Nagaraja
The volatile scandium-β-diketonates are synthesised using acetylacetone (acac) and tetramethylheptanedione (tmhd) as coordinative
ligands for CVD application. The X-ray powder patterns are indexed and analysed and found to be orthorhombic and monoclinic
phases for Sc(acac)3(1) and Sc(tmhd)3(2) respectively. The sublimation and evaporation kinetics have been analyzed using three calculating techniques. The non-isothermal
based activation energy values are found to be 38 ± 2 and 73 ± 2 kJ mol−1 by Flynn–Wall technique for (1) and (2) respectively. The measured Ea values are close to the value obtained using Kissinger method.
Authors:E. Filatov, S. Sysoev, Ludmila Zelenina, Tamara Chusova, V. Logvinenko, P. Semyannikov, and I. Igumenov
of a series of lithium β-diketonates: Li(dpm) (dpm=dipivaloylmethanate
(2,2,6,6-tetramethylheptane-3,5- dionate)), Li(pta) (pta=pivaloyltrifluoracetonate
(2,2-dimethyl-6,6,6-trifluoro-3,5-hexanedionate)), Li(tfa) (tfa=trifluoracetylacetonate
(1,1,1-trifluoro-2,4-pentandionate)), Li(hfa) (hfa=hexafluoracetylacetonate
(1,1,1,5,5,5-hexafluoro-2,4-pentandionate)) has been investigated. Gas phase
composition of these complexes has been established. Temperature dependences
of vapor pressure of lithium compounds were obtained by static and dynamic
methods, and thermodynamic parameters were calculated. Dependence of compound
volatility on ligand structure is shown. For Li(dpm) detailed investigation
has been done by differential scanning calorimetry (DSC).
Authors:Ksenia Zherikova, Natalia Morozova, Ludmila Zelenina, S. Sysoev, Tamara Chusova, and I. Igumenov
Five volatile hafnium(IV) and zirconium(IV) β-diketonates: hafnium(IV) acetylacetonate, hafnium(IV) trifluoroacetylacetonate,
hafnium(IV) pivaloyltrifluoroacetonate, hafnium(IV) 2,2,6,6-tetramethylheptane-3,5-dionate and zirconium(IV) 2,2,6,6-tetramethylheptane-3,5-dionate
were obtained, purified and identified. Thermal behavior of solid compounds was investigated by thermogravimetry (TG) and
differential scanning calorimetry (DSC) in helium atmosphere and in vacuum. DSC method was also used for definition of thermodynamic
characteristics of melting processes. Using the static method with quartz membrane zero-manometer and the flow method the
temperature dependencies of saturated vapor pressure for hafnium(IV) complexes was obtained. The standard thermodynamic characteristics
ΔHT0 and ΔST0 of sublimation and evaporation processes were calculated from the temperature dependences of saturated vapor pressure.
Authors:V. Lazarev, J. Greenberg, Z. Ozerova, and G. Sharpataya
DSC and vapour pressure measurements are presented on some Be, Al and Cr complexes with 2,4-pentanedione tetramethyl-3,5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione and hexafluoro-2,4-pentanedione. Thermodynamic functions are given for the sublimation, vaporization and melting processes of the substances.
The standard molar enthalpies of formation of the crystalline lanthanum(III) chelate complexes with pentane-2,4-dione (acetylacetone, Hacac) and 1-phenylbutane-1,3-dione (benzoylacetone, Hbzac) were determined by the solution calorimetry method. The following values ofΔH
Authors:H. Shoji, Y. Maruyama, K. Ogawa, Y. Oki, and N. Ikeda
A series of metal -diketonates were irradiated with bremsstrahlung of maximum energy of 50 MeV and the recoil behavior of7Be, formed from12C of ligands through12C(, n)7Be reaction, was investigated.7Be nuclides thus formed were detected partially as central metal atoms of the complexes. Complex yields of7Be were compared and an anomalously high yield was observed in tris-acetylacetonatocobalt(III) [Co(acac)3].
Authors:A. Davidov, M. Isenberg, E. Fedoseev, and S. Travnikov
Trace amounts of lanthanum hexafluoroacetylacetonate and indium acetylacetonate were isolated by combination of methods, which includes synthesis of volatile elements -diketonates by nucleophilic ligands exchange and fractional sublimation. This method is useful for produce isotope generators.
Authors:E. Fedoseev, M. Aizenberg, S. Timokhin, S. Travnikov, I. Zvara, A. Davydov, and B. Myasoedov
Volatile hexafluoroacetylacetonates of hafnium, ytterbium, scandium, as well as scandium trifluoroacetylacetonate and acetylacetonate have been obtained by interaction of -diketone vapours with radionuclides formed in a cyclotron in on-line operation. The application of volatile -diketonates for transport and separation of the short-life isotopes of metallic elements has been shown.
Authors:V. A. Logvinenko, N. E. Fedotova, I. K. Igumenov, and G. V. Gavrilova
Thermal dissociation processes ofβ-diketonate adducts with the composition ML2 · 2B (L = acetylacetone and its substituted derivatives;M = Ni, Co;B = H2O, BuNH2CH3OH, Py, NH3) were investigated. Kinetics of dissociation were studied in a flow reactor. For dehydration processes a compensation relationship is observed (lgA=E+b), demonstrating analogous mechanisms.