| Autor: |
Kayumova, D. B., Tereshchenko, D. S., Shatalova, T. B., Lermontova, E. Kh., Boltalin, A. I., Morozov, I. V., Malkerova, I. P., Alikhanyan, A. S. |
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| Zdroj: |
Russian Journal of Coordination Chemistry; Dec2022, Vol. 48 Issue 12, p870-876, 7p |
| Abstrakt: |
A new trinuclear triangular cobalt complex (NMe4)[Co3(μ3F)(TFA)6(Py)3] (I) is synthesized by crystallization from a methanol solution. The crystal structure of complex I is solved by single-crystal X-ray diffraction analysis (CIF file CCDC no. 2151075). The Knudsen effusion method combined with mass spectral analysis of gaseous vaporization products shows that the heating of complex I under reduced pressure results in the removal of (CH3)4NF as (CH3)3N and CH3F and of pyridine to form anhydrous cobalt trifluoroacetate Co(CF3COO)2, which sublimes on further heating to the monomer and dimer. The decomposition of Co(CF3COO)2 with the formation of CoF2 and release of CO2 and COF2 occurs along with sublimation. Experiments on the iso- and polythermal vaporization makes it possible to calculate the partial pressures of the major gaseous products, to determine the standard enthalpies of sublimation of the monomer (137.9 ± 12.2 kJ/mol) and dimer (147.0 ± 21.6 kJ/mol) in a temperature range of 460–540 K, and to find the enthalpy of dissociation of the dimer (128.8 ± 25.8 kJ/mol). The study of the thermal stability of complex I in an argon flow (p = 1 atm) by gravimetry combined with mass spectral analysis of gaseous products confirms the three-stage decomposition of complex I. Unlike heating in vacuo, no sublimation of Co(TFA)2 is observed under these conditions, and the decomposition of Co(TFA)2 results in the formation of CoF2 and is accompanied by the release of gaseous (CH3)3N, CH3F, Py, CO, CO2, CHF3, СF3COF, (CF3CO)2O, CF3COCF3, and C2F4. The presence of moisture and oxygen traces in argon leads to a decrease in the content of easily hydrolyzed products and formation of the oxidation and hydrolysis products: H2O, HF, and CF3COOH. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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