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.

Revision of the gas-phase acidity scale below 300 kcal mol(-1).

The gas-phase acidity (GA) scale from (CF(3)CO)(2)NH to (C(2)F(5)SO(2))(2)NH--about a 24 kcal mol(-1) range of gas-phase acidities--was reexamined using the Fourier transform ion cyclotron resonance equilibrium measurement approach. Some additions and modifications to the standard methodology of GA measurements were introduced (estimation of partial pressures from mass spectra of the compounds, instead of the pressure gauge readings and use of long reaction times) to achieve higher reliability. Gas-phase acidities of 18 compounds were determined for the first time.

Alkyl derivatives of bis(perfluoroalkylsulfonylimino)trifluoromethanesulfonic acid.

N-methyl and N-ethyl derivatives of N-(trifluoromethylsulfonyl)-[N'-(trifluoromethylsufonyl)-trifluoromethylsulfoximidoyl] imides 2a,b were prepared by alkylation of bis(trifluoromethylsulfonylimino)trifluoromethanesulfonic acid 1 or its silver salt 1a. It turns out that these imides are strong alkylating agents in spite of the fact that Me (Et) groups are attached to nitrogen atom. The alkylating activity of n-PrI, i-PrI, n-BuI, and n-AmI in the presence of silver salt of bis(trifluoromethylsulfonylimino)trifluoromethanesulfonic acid 1a was investigated.

New kinds of organic superacids. Bis(perfluoroalkylsulfonylimino)trifluoromethanesulfonic acids and their trimethylsilyl esters.

A synthesis of new unsymmetric trifluoromethylsulfonylimino(nonafluoro-n-butyl-sulfonylimino)trifluoromethanesulfonic acid (1b) is reported. During the silylation reactions studies of bis(perfluoroalkylsulfonylimino)trifluoromethanesulfonic acids (1a,b) it was shown that reaction proceeds exclusively on the central oxygen atom to give trimethylsilyl esters. The obtained esters along with several trimethylsilylesters of sulfonic acids have been studied by 29Si-NMR spectroscopy and an attempt to estimate the strength of bis(perfluoroalkylsulfonylimino)trifluoromethanesulfonic acids by the 29Si-NMR chemical shifts of their trimethylsilylesters was made, resulting in the conclusion that these compounds may be cited as the strongest organic Brønsted acids.

Synthesis of new organic super acids-N-(trifluoromethylsulfonyl)imino derivatives of trifluoromethanesulfonic acid and bis(trifluoromethylsulfonyl)imide.

Salts of N-trifluoromethylsulfonyl derivatives of trifluoromethyl- and phenylsulfonimidoyl imides have been synthesized by two different routes. Both methods are one-pot reactions, that run in mild conditions with good yields. Two novel organic super acids: bis[N-(trifluoromethylsulfonyl)trifluoromethanesulfonimidoyl]imide and N,N'-bis(trifluoromethyl-sulfonyl)diimino trifluoromethanesulfonic acid were prepared and the structure of their potassium salts was obtained by single-crystal X-ray diffraction.