Yurii L. Yagupolskii

Equilibrium acidities of superacids.

In this paper, we report the most comprehensive equilibrium superacidity scale that is available to date. Contrary to most of the past works, this scale is set up in a medium of constant composition and the obtained acidity values characterize the acidities of molecules rather than acidities of media. The current scale is thus complementary to the well-known H(0) scale in the information that it provides. The solvent used is 1,2-dichloroethane (DCE). DCE has very weak basic properties (but sufficiently high polarity) and is an appropriate solvent for measuring acidities of very strong acids of diverse chemical nature. DCE acidities of well-known superacids (CF(3)SO(2)OH, (CF(3)SO(2))(2)NH, cyanocarbon acids, etc.) as well as common mineral acids (H(2)SO(4), HI, HBr, etc.) are reported. Acidities of altogether 62 acids have been determined from 176 interlinked relative acidity measurements. The scale spans 15 orders of magnitude (from picric acid to 1,1,2,3,3-pentacyanopropene) and is expected to be a useful tool in design, use, and further acidity measurements of superacidic molecules.

A new synthesis of trifluoromethanethiolates—characterization and properties of tetramethylammonium, cesium and di(benzo-15-crown-5)cesium trifluoromethanethiolates

Abstract [NMe4]SCF3, CsSCF3 and [(B-15-C-5)2Cs]SCF3 (B-15-C-5: benzo-15-crown-5) are formed from reactions of the corresponding fluorides, trimethyl(trifluoromethyl)silane, Me3SiCF3, and elemental sulfur in glyme or THF. All compounds are colorless to pale ochre solids decomposing significantly above ambient temperature. Excellent agreement between experimental and theoretical vibrational frequencies, calculated at the B3PW91 level of theory, impressively confirms the salt-like nature of [NMe4]SCF3. The properties of the title compounds as nucleophilic SCF3 transfer reagents were checked with a variety of organic, organometallic and inorganic compounds.

Characteristics of the electrolyte with fluoro organic lithium salts

Some fluoro organic lithium salts have attractive features as organic electrolyte such as solubility, conductivity, and oxidation potentials. The fluoro organic lithium salts with SO 2 groups show higher conductivities than those with CO groups. Methide (CF 3 SO 2 ) 3 CLi and imide (RfSO 2 ) 2 NLi salts show higher conductivities than oxide salts RfSO 2 OLi with only one RfSO 2 group. The lithium salts with long fluoroalkyl groups and two or more RfSO 2 groups show high oxidation potentials and high aluminum corrosion potentials over 4.3 V. The battery performances of modified imide salts such as (C 2 F 5 SO 2 ) 2 NLi, (C 4 F 9 SO 2 )(CF 3 SO 2 )NLi, and ((CF 3 ) 2 CHOSO 2 ) 2 NLi are satisfactory. The cycle characteristics of the imide salt cells are better than those of the LiPF 6 cell. Especially, the ((CF 3 ) 2 CHOSO 2 ) 2 NLi shows the best cycle characteristics. In XPS analysis the anode surfaces of the imide cells are covered with imide salt components.

Nucleophilic trifluoromethylation of organic substrates using (trifluoromethyl)trimethylsilane in the presence of a fluoride anion II. A convenient route to aryltrifluoromethyl-sulfides, -sulfoxides and -sulfones☆

Abstract Aryltrifluoromethyl-sulfides, -sulfoxides and -sulfones can be prepared by trifluoromethylation of the corresponding arylsulfenyl, -sulfinyl and -sulfonyl halides using (trifluoromethyl)trimethylsilane in the presence of fluoride sources, such as TASF [tris(dimethylamino)sulfonium difluorotrimethylsilicate].

Electronic structures and electrochemical properties of LiPF6-n(CF3)n

We evaluated (1) thermal and electrochemical stability and (2) ion-dissociation ability of PF 6-n (CF 3 ) n anions by computational method. The thermal stability order by ΔΔE (anion) is PF 4 (CF 3 ) - 2 > PF 5 (CF 3 ) > PF 3 (CF 3 ) - 3 > PF - 6 . The ion-dissociation ability order by ΔΔE (Li salts) is LiPF 3 (CF 3 ) 3 > LiPF 4 (CF 3 ) 2 > LiPF 5 (CF 3 ) > LiPF 6 . The conductivity of electrolyte solution with LiPF 4 (CF 3 ) 2 (3.9 mS/cm) was a little lower than that of LiPF 6 (4.4 mS/cm) in 0.1 mol/l Li salt/PC:DME electrolyte, while the oxidation potential of LiPF 4 (CF 3 ) 2 in PC was higher than that of LiPF 6 . The LiPF 4 (CF 3 ) 2 -cell showed better cycle characteristics than LiPF 6 -cell.

Trifluoromethylation of heterocumulenes with trimethyl(trifluoromethyl)silane in the presence of fluoride ions: synthesis of trifluoroacetamides and trifluorothioacetamides from isocyanates and isothiocyanates

Abstract Trimethyl(trifluoromethyl)silane reacts in the presence of fluoride ions with isocyanates and isothiocyanates under mild conditions to give corresponding trifluoroacetamides and trifluorothioacetamides in high yields.

Perfluoroalkylation of heterocumulenes with trimethyl(perfluoroalkyl)silanes in the presence of fluoride ions: synthesis of perfluoroalkanesulfinyl amides from N-organylsulfinyl amines

Trimethyl(perfluoroalkyl)silanes react in the presence of fluoride ions with N-organylsulfinylamines under mild conditions to give the corresponding perfluoroalkanesulfinyl amides in high yields.

Synthesis and properties of N-perfluoroalkylsulfonyltriarylbismuth imines, Ar3BiNSO2Rf

Abstract Bismuth imines of the general formula Ar 3 BiNSO 2 R f have been prepared either by the reaction of Ar 3 BiCl 2 with the corresponding perfluoroalkylsulfonic acid amide in the presence of NaOCH 3 or by the reaction of Ar 3 BiF 2 with CF 3 SO 2 N[Si(CH 3 ) 3 ] 2 . Bismuth imines Ar 3 BiNSO 2 R f as well as (C 6 H 5 ) 3 BiNSO 2 (4-CH 3 C 6 H 4 ) were obtained as crystalline solids and characterized by NMR spectroscopy, elemental analysis and consecutive reactions.

Carbenoid reactions of trifluoromethylelement compounds. Part 4. Reactions of trifluoromethylzinc bromide with enamines and methylene bases

Abstract The reactions of ZnBr(CF 3 )·2CH 3 CN with 1-morpholinocyclo-pentene and -hexene have been investigated and found to yield mixtures of two isomers of 1-morpholino-1-cyanomethyl-2-difluoromethyl-cyclopentane and -hexane, respectively. The interaction with methylene bases of nitrogen heterocycles leads to the formation of trimethinecyanine dyes. This reaction sequence includes the formation of two carbon-carbon bonds in a one-pot operation. The mechanism of the reactions is discussed.

Efficient synthesis of N-(trifluoromethylsulfonyl)trifluoromethanesulfonimidoyl fluoride – the key agent in the preparation of compounds with superstrong electron-withdrawing groups and strong acidic properties

N-(Trifluoromethylsulfonyl)trifluoromethanesulfonimidoyl fluoride 4 was prepared by the oxidative fluorination of N-(trifluoromethylsulfinyl)trifluoromethanesulfonamides 3a,b which are formed by the reaction of trifluoromethyltrimethylsilane with N-(sulfinyl)trifluoromethanesulfonamide in the presence of fluoride ions. Addition of MF to N-(sulfinyl)trifluoromethanesulfonamides affords the stable N-(fluorosulfinyl)trifluoromethanesulfonamides 2a,b. Reaction of 4 with N-nucleophiles readily forms the corresponding amides 6–8.