15429-03-5Relevant articles and documents
Selenoyl-trifluoroacetone: Synthesis, properties, and complexation ability towards trivalent rare-earth ions
Lutoshkin, Maxim A.,Taydakov, Ilya V.
, (2021)
The selenium-containing analog of thenoyl-trifluoroacetone has been synthesized and first characterized by UV–visible and NMR-spectroscopies. Synthesis of selenoyltrifluoroacetone was performed by a two-step procedure: acetylation of selenophene and interaction of 2-acetylselenophene with ethyl-trifluoroacetate. The structure of the obtained product has been confirmed using NMR, EI-MS, and elemental analysis. Spectral, acid-base, complexing, and keto-enol parameters were studied under various conditions. Received values of dissociation and protonation constants characterize selenoyltrifluroracetone as a stronger acid and stronger base than acetylacetone. The aqueous chelation with sixteen rare-earth metals has been studied in acetate and glycine buffer media at I = 0.5 M (NaCl). Values of logK non-monotonically increase from La(III) to Lu(III) and lay within the range of 4.5–11.5 logarithmic units. Most of the determined formation constants were higher than analogous values for thenoyl- and furoyl-trifluoroacetone rare-earth metal complexes. Thermodynamic and spectral parameters were simulated using both DFT and TD-DFT approaches.
Kinetics of the enolisation reactions of 3-acetyl-2,5-dimethylfuran and of 2-acetylselenophene
De Maria, Paolo,Fontana, Antonella,Siani, Gabriella,Spinelli, Domenico
, p. 1867 - 1872 (1998)
Rate constants for the enolisation reactions of title compounds have been measured by their rates of halogenation at 25 °C in water, in several buffers, in dilute hydrochloric acid, in dilute sodium hydroxide, and in the presence of some metal ion salts. The results have been compared with those previously obtained from the corresponding reactions of acetophenone and a number of other acetyl heterocycles. Electronegativity of the heteroatoms and the "π-excessive" nature of the heterocyclic rings appear to be the main factors determining the relative reactivities in the acid-catalysed reactions. Bronsted β values and isotope effects, kH/kD, point to a more symmetrical transition state for the investigated acetyl heterocycles than that for acetophenone in the general base-catalysed reaction. Metal-activating factors (MAF), i.e. the catalytic constant for metal-ion (Cu2+, Zn2+, and Ni2+) catalysis, kM, relative to that for proton catalysis, kH, are discussed as an empirical measure of the "hard or soft" character of the carbonyl groups in acyl heterocycles.
