Trifluoromethyl Sulfide Research Articles

One-Pot Telescoping S-Transfer and Trifluoromethylation for the Synthesis of 2-CF3S-Imidazoles with N-Oxides as Convenient Precursors.

Readily available 2-unsubstituted imidazole N-oxides were examined as starting materials for the preparation of fully substituted 1,4,5-aryl/alkyl 2-trifluoromethylsulfanyl-imidazoles. Whereas activation of the N-oxide function followed by attempted nucleophilic addition of the -SCF3 was in vain, the alternative approach involving "sulfur transfer reaction" and subsequent electrophilic trifluoromethylation with Togni reagent provided target products in high yield via a one-pot procedure. The structure of representative enantiomerically pure imidazol-2-yl trifluoromethyl sulfide was confirmed by X-ray analysis.

Revealing the mechanisms of electrolyte additive PTS on Ni-rich electrode: Tolerance to high temperature (50 °C) and high voltage (4.6 V)

Ni-rich (Ni≥0.8) LiNixCoyMn1−x−yO2 (NCM) cathode materials have attracted great interest for high-energy-density lithium ion batteries (LIBs). However, layered oxides of Ni-rich CAMs are suffering from the notorious structural and interfacial degradation in the liquid electrolyte, especially at high state-of-charge (voltage) and temperature, which leads to electrochemical performance deterioration and thermal runaway of the cell. This work systematically and comprehensively reveals the underlying mechanism of the electrolyte additive phenyl trifluoromethyl sulfide (PTS) to enhance the electrochemical property of Ni-rich layered oxides at high voltage (∼4.6 V) and high-temperature (∼50 °C). Specifically, PTS observably encourages the electrode stability via cathode-electrolyte interface strengthening and reactive oxygen species deactivating mechanism, which facilitates the NCM811 cathode to adapt to the deep charging state as well as the highly oxidized environment. The binding energy calculation results reveal that the superoxide radical could steadily adsorb on the S radical or Li+ sites by interacting with Li+, thus making the superoxide radical deactivated. With the interface strengthening of PTS, the Ah-level NCM811||Gr pouch cell exhibits excellent cycling stability. This work affords a guide to designing electrolytes for Ni-rich LIBs towards high-voltage and high-temperature.

Formation mechanism of protective interphase for high voltage cathodes by phenyl trifluoromethyl sulfide

The formation mechanism of protective interphases on high voltage cathodes of lithium ion batteries, resulting from phenyl trifluoromethyl sulfide (PTS) as an electrolyte additive, is understood through theoretical calculations, and confirmed by evaluating the cyclic stability of a lithium-rich cathode, Li1·2Mn0·54Ni0·13Co0·13O2, in the electrolytes with and without PTS. It is found that PTS is oxidized through the transferring of one fluorine atom from methyl to phenyl and the subsequent breaking of bond S–C in phenyl, yielding fluorobenzene and sulfur-contained radical that construct mainly the protective interphase. With this interphase formed from PTS, the cyclic stability of Li1·2Mn0·54Ni0·13Co0·13O2 is significantly improved. The capacity retention of Li1·2Mn0·54Ni0·13Co0·13O2 in 1.0 M LiPF6-EC/EMC/DEC (3/5/2 by weight) at 0.5C after 200 cycles is enhanced from 39% to 83% by adding 0.5% PTS.

Nickel-catalyzed aryl trifluoromethyl sulfide synthesis: a DFT study

A Ni(i)/Ni(iii) catalytic cycle allows aryl trifluoromethyl sulfides to be obtained at room temperature from [NMe4][SCF3] and aryl halides.

Synthesis of o-Methyl Trifluoromethyl Sulfide Substituted Benzophenones via 1,2-Difunctionalization of Aryne by Insertion into the C-C Bond.

An efficient process for the preparation of valuable o-methyl trifluoromethyl sulfide substituted benzophenones has been developed. The transition-metal-free method features insertion of aryne into a C-C σ-bond under mild reaction conditions for the first time to achieve ortho-difunctionalized arenes containing a pharmaceutically important trifluoromethylthio functional group. A wide substrate scope has been demonstrated for the developed protocol.

Trifluoromethylthiolation of Unsymmetrical λ3‐Iodane Derivatives: Additive‐Free, Selective and Scalable Introduction of the SCF3 Group

AbstractThe reaction of copper trifluoromethyl sulfide with diaryliodonium salts provides a straightforward pathway for the synthesis of aryl trifluoromethyl thioethers under mild reaction conditions and within short reaction times. High chemoselectivity was achieved by using mesityl as a leaving group. A large range of novel [(het)aryl](mesityl)iodonium salts underwent this reaction under the optimized conditions to give the desired products in moderate to good yields.

A novel electrolyte additive for improving the interfacial stability of high voltage lithium nickel manganese oxide cathode

In this work, we propose a novel electrolyte additive phenyl trifluoromethyl sulfide (PTS) to improve the interfacial stability of high voltage lithium nickel manganese oxide (LiMn1.5Ni0.5O4) cathode/electrolyte. At 1C rate, addition of 0.5% PTS improves the capacity retention of LiNi0.5Mn1.5O4 from 65% to 84% after 450 cycles at room temperature, and from 64% to 95% after 100 cycles at evaluate temperature. Density functional theory calculation and experimental characterization demonstrate that PTS oxidizes preferentially to the carbonate base electrolyte, generating a SEI film, which effectively suppresses the continuous decomposition of carbonate base electrolyte and the structural destruction of LiMn1.5Ni0.5O4.

Pd‐Catalyzed Synthesis of ArSCF3 Compounds under Mild Conditions

Pd‐Catalyzed Synthesis of ArSCF₃ Compounds under Mild Conditions

ChemInform Abstract: Synthesis, Structure and Reactivity of a Trifluoromethyl Sulfide Anionic Salt Stabilized with Tetrakis(dimethylamino)ethylene Dication (TDAE2+).

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Studies on Reactions of Thioketones with Trimethyl(trifluoromethyl)silane Catalyzed by Fluoride Ions

Treatment of 2,2,4,4-tetramethylcyclobutane-1,3-dione (6) in THF with CF3SiMe3 in the presence of tetrabutylammonium fluoride (TBAF) yielded the corresponding 3-(trifluoromethyl)-3-[(trimethylsilyl)oxy]cyclobutanone 7 (Scheme 1) via nucleophilic addition of a CF anion at the CO group and subsequent silylation of the alcoholate. Under similar conditions, the ‘monothione' 1 reacted to give thietane derivative 8 (Scheme 2), whereas in the case of ‘dithione' 2 only the dispirodithietane 9, the dimer of 2, was formed (Scheme 3). A conceivable mechanism for the formation of 8 is the ring opening of the primarily formed CF3 adduct A followed by ring closure via the S-atom (Scheme 2). In the case of thiobenzophenones 4, complex mixtures of products were obtained including diarylmethyl trifluoromethyl sulfide 10 and 1,1-diaryl-2,2-difluoroethene 11 (Scheme 4). Obviously, competing thiophilic and carbophilic addition of the CF anion took place. The reaction with 9H-fluorene-9-thione (5) yielded only 9,9′-bifluorenylidene (14; Scheme 6); this product was also formed when 5 was treated with TBAF alone. Treatment of 4a with TBAF in THF gave dibenzhydryl disulfide (15; Scheme 7), whereas, under similar conditions, 1 yielded the 3-oxopentanedithioate 17 (Scheme 9). The reaction of dithione 2 with TBAF led to the isomeric dithiolactone 16 (Scheme 8), and 3 was transformed into 1,2,4-trithiolane 18 (Scheme 10).

Synthesis, structure and reactivity of a trifluoromethyl sulfide anionic salt stabilized with tetrakis(dimethylamino)ethylene dication (TDAE2+)

A synthesis of the stable ionic trifluoromethanethiolate salts, TDAE2+2SCF3− (1) and TDAE2+SCF3−Cl− (2) was accomplished in quantitative yields via reduction of bis(trifluoromethyl) disulfide and trifluoromethanesulfenyl chloride using tetrakis(dimethylamino) ethylene (TDAE). The salts were found to be stable up to their melting points. The trifluoromethanethiolate salt [TDAE2+2SCF3− (1)] was for the first time characterized by X-ray structural analysis (orthorhombic, Pbca, a = 1434.0(1), b = 1178.1(1), c = 2203.2(1) pm) and cyclic voltammetry. Several reactions show the synthetic utility of this new reagent.

Reactions of silver(I) trifluoromethanethiolate with halotrimethylsilanes: in situ generation of trimethylsilyl trifluoromethyl sulfide

Silver(I) trifluoromethanethiolate reacts with halotrimethylsilanes to produce silver halide, fluorotrimethylsilane and an oligomeric species of formula (CS) 3 (SCF 3) 2. Variable temperature 19F NMR spectroscopy reveals that the reaction proceeds via trimethylsilyl trifluoromethyl sulfide (Me 3SiSCF 3), which rapidly decomposes on warming. This acts as a source of nucleophilic trifluoromethanethiolate, reacting with highly activated haloaromatics to produce trifluoromethyl aryl sulfides.

ChemInform Abstract: Trifluoromethylthio‐ and Pentafluorophenylthio‐substituted Alkenes and Arylalkenes.

AbstractThe reactions between copper trifluoromethyl sulfide (IIa) or copper pentafluorophenyl sulfide (IIb) and the five differently substituted alkenes (I), (IV), (VI), (VIII) and (X) afford the title compounds (III), (V), (VII), (IX) and (XI).

Drug Retention during Animal Inhalation Exposure by FT-IR Spectroscopy

A unique analytical method for the determination of the amount of volatile drug retention by animals during inhalation exposure experiments was developed and evaluated. A large-volume collection system was used to collect and store all exhaled air from the animal. The collected air was analyzed by FT-IR spectroscopy with the use of a Nicolet 5SXB spectrometer and a Spectra-Tech Inc. 10-m long-path gas cell. The developed technique was evaluated with the use of bis-(trifluoromethyl) disulfide (TFD) administered to adult sheep. Control experiments confirmed the system's ability to capture 100% of the administered compound. It was observed that the sheep retained an average of 4.4 mg of this compound per kg of body weight during a 10-min exposure period at an air concentration of 5.0 mg per L. After quantitative analysis, compounds exhaled by the animal were concentrated by passing the collected air through a series of dry-ice and liquid-nitrogen-cooled traps. FT-IR analysis of the collected concentrated products indicated that TFD did not undergo chemical decomposition to form trifluoromethyl sulfide during the exposure experiment. The exposure system and the analytical method developed can be used with both large and small animals.

Preparation of bromodifluoromethyl sulfide and its conversion to trifluoromethyl sulfide

Bromodifluoromethyl sulfides are prepared by the reaction of mercaptides with CF 2BrX (x=Br,Cl). And treatment of bromodifluoromethyl sulfides with various inorganic fluorides produced trifluoromethyl sulfides.