Journal of Fluorine Chemistry最新文献

A series of six, 4-substituted 2,3,5,6-tetrafluoropyridine (TFP) hetero ethers have been synthesized via regio-selective, nucleophilic aromatic substitution (SNAr) of pentafluoropyridine with aliphatic alcohols and phenols. Furthermore, the hexyloxy modified TFP substrate also served as a synthetic intermediate for the preparation of 3,5-difluoro-4-(hexyloxy)-2,6-di(1H-imidazol-1-yl)pyridine, as well as 4-(hexyloxy)-2,3,5,6-tetra(1H-pyrazol-1-yl)pyridine, which offers a terpyridine scaffold. This work outlines their synthetic methodology in addition to detailing the TFP intermediates’ unexpected reactivity with imidazole and pyrazole nucleophiles

A photoredox-catalyzed decarboxylative α-monofluoroalkylation of silyl enol ethers with fluoroalkyl carboxylic N-(hydroxy)phthalimide esters has been successfully developed. Diverse functionalized α-monofluoroalkyl acetophenones were produced in modest to good yields under mild and operationally simple conditions. The developed method was further applied to synthesize antalgic and ataractic activity compound containing α-monofluoroalkyl acetophenone skeleton.

A halon-free method for the synthesis of gem‑bromofluoroolefins utilizing ethyldibromofluoro-acetate is disclosed via a Wittig type reaction. The reaction system takes advantage of inexpensive and readily available reagents. The method was applied to a wide variety of aryl aldehydes. Both electron donating and electron withdrawing moieties on the aryl ring were tolerated and the desired olefin products were obtained in good to excellent yields.

By reacting CeF₃ with XeF₂ the anhydrous CeF₄ was synthesized and studied by XRD, SEM, FTIR, ¹⁹F NMR spectrometry and thermogravimetry. It was found that CeF₄ undergoes hydration upon keeping in air forming the crystalline hydrate with the approximate formula [CeF₄•0.2H₂O]*0.7H₂O. Water molecules both enter the coordination sphere of cerium and form crystalline hydrates with cerium(IV) fluoride due to OH…F hydrogen bonds in the crystal lattice.

In this work, we present a new method for the facile preparation of aryl-IF₄ compounds using KF and ex situ generated chlorine gas within a two-chamber reactor setup. Notably, the process stands out for its simplicity by omitting the use of specialized equipment and generating less chemical waste than the previously reported works. While demonstrating high efficiency at room temperature, the novel approach provides access to a diverse array of products with moderate to excellent yields.

The synthesis of (trifluoromethyl)alkenes, including fully substituted variants, was achieved from thioketones with in situ-generated (trifluoromethyl)diazoalkanes [CF₃C(R)=N₂] (the Barton–Kellogg reaction). In the presence of sodium methoxide and a catalytic amount of tetrabutylammonium chloride, trifluoromethylated N-tosylhydrazones [CF₃C(R)=NNHTs] derived from trifluoroacetaldehyde hemiacetal (R = H) or trifluoromethyl ketones (R = aryl or alkyl) were employed in the reactions with thioketones. The resulting (trifluoromethyl)diazoalkanes reacted with thioketones, forming (trifluoromethyl)thiirane intermediates. Treatment of these intermediates with trimethyl phosphite readily afforded the substituted (trifluoromethyl)alkenes. Theoretical calculations (DFT, B3LYP/6-31G*) showed that (trifluoromethyl)thiiranes, with less distortion than 2,2-difluorothiiranes, exhibited lower reactivity. Consequently, the involvement of a reducing agent was deemed necessary for the desulfurization step.

The research on SF₆ degradation and conversion is of great significance for environmental protection. Based on the density functional theory, the adsorption process of SF₆ on the TiO₂(001) and TiO₂(101) surfaces was investigated. The results indicate a strong interaction between SF₆ and the TiO₂ surface. Significant structural changes in the SF₆, such as elongation of the S-F bonds, were observed after adsorption, rendering the SF₆ more prone to decomposition. According to Mulliken charge analysis, electron transfer occurs from the TiO₂ surface to the SF₆, revealing SF₆ as an electron acceptor while TiO₂ acts as an electron donor. Analysis of the density of states confirms a pronounced electronic orbital overlap between the S/F atoms of SF₆ and the Ti/O atoms of TiO₂, and the charge density distribution along the Z-axis further supports this charge transfer process. Additionally, experimental studies have demonstrated that TiO₂ photocatalysis can accelerate the degradation of SF₆ during DBD. This study demonstrates the catalytic potential of TiO₂ in the degradation of SF₆ insulating gas and provides theoretical support for the efficient and harmless treatment of SF₆.

The interaction of tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato)europium(III), (Eu(FOD)₃), with xenon difluoride in acetonitrile solution was found to be accompanied by chemiluminescence (CL). The kinetic curve of CL at a ratio of reagents Eu³⁺/XeF₂ of 1:2 has a complex form; an initial rapid decrease is replaced by an increase in CL intensity, the maximum of which is reached approximately 10 min after the start of the reaction. Next, an exponential decay of the CL intensity is observed over several tens of minutes. The CL spectrum is located in the wavelength range 400–750 nm and corresponds to the emission of an electronically excited europium (III) ion coordinated with FOD and fluoride ion. Spectral methods were used to identify the reaction products – europium (III) fluoride in the sediment and oxygen difluoride in the gas phase. A mechanism for chemiexcitation of europium(III) has been proposed, including: 1) acceptance of fluorine anion from the XeF₂ molecule by europium ion with the formation of active intermediate XeF⁺; 2) oxidative fluorination of the ligand, which is initiated by the interaction of oxygen atom of the FOD ligand with XeF⁺ cation and ends with the formation of oxygen difluoride and the electronically excited product P*, presumably a fluorinated ketone; 3) non-radiative transfer of excitation energy from P* to the europium ion within its coordination sphere, followed by its radiative deactivation.