C. de Loze

Triple ion formation in solutions of alkaline sulfocyanides

Through the infrared and Raman spectra of alkaline sulfocyanides in high-and low-polarity media, nitromethane (CH3NO2) and tetrahydrofuran (THF), triple cations and triple anions may be characterized. The formation of these species at the expense of ion pairs or more aggregated species such as dimers is discussed taking into account cation solvation, anion solvation, and the influence of cation-anion interaction.

Anion solvation III. Infrared spectroscopic determination of solvent acceptor numbers and their use in understanding anion solvation

It is shown that the Gutmann acceptor number determined by NMR for a number of solvents correlates with vibration frequencies of these solvents. Vibration spectroscopy is applied to the determination of acceptor numbers to characterize the solvation of anions. The acceptor number obtained by this method characterizes the anion solvation in all its states of association with the cation.

Anion solvation II. Solvation of thiocyanate and halide anions in mixtures of protic and aprotic solvents

Infrared and Raman spectra of tetraalkylammonium and lithium thiocyanates and bromides in protic-aprotic solvent mixtures have been recorded in the 2100–2300 cm−1 region at room temperature. It is shown that the anion is hydrogen bonded to the protic solvent, whether free or linked to a cation. Models are given for the solvated ion-pair taking into account both anion and cation solvation.

Anion solvation I. Solvation of the thiocyanate anion in aprotic solvents by near infrared spectroscopy

Solutions of tetrabutylammonium and lithium thiocyanates have been examined in the infrared 2000–5500 cm−1 region at room temperature. New bands have been observed which can be assigned to simultaneous transitions between the v (CN) vibrations of the anion and the v (CH) vibrations of the solvent CH3 group. These transitions which are independent of the state of association (free ion, ionpairs, dimers, triple cation) provide evidence of anion solvation by aprotic solvents.

Etude spectroscopique de derives mercuriques d'amides-thiols: Partie III. Spectres de vibration et structure de complexes mercuriques des thiol-2N-méthylacétamide, thiol-3N-méthylpropanamide et N-thiol-2 éthyle)acétamide

Abstract Raman and IR spectra of (CH 3 NHCOCH 2 S) 2 Hg, (CH 3 CONHCH 2 CH 2 S) 2 Hg and CH 3 NHCOCH 2 CH 2 SHgCl have been recorded between 3800 and 60 cm −1 . Mercury is covalently bonded to two sulphur atoms in the first two compounds and to one sulphur atom and one chlorine atom in the third compound. (CH 3 NHCOCH 2 S) 2 Hg forms a tenatom ring by intramolecular hydrogen bonding NH⋯OC. In the two other complexes, weak interactions Hg⋯O are consistent with experimental results.

Etude spectroscopique de derives mercuriques d'amides-thiols: I. Spectres de vibration et structure des thiol-2 N-méthylacétamide, thiol-3 N-méthylpropanamide et N-(thiol-2 éthyle) acétamide

Abstract Raman and infrared spectra of CH3NHCOCH2SH, CH3NHCO(CH2)2SH and CH3CONH(CH2)2SH have been recorded between 3800 and 200 cm−1. Some structural information is obtained from their analysis: for pure liquids or solids, molecules form linear chains with NH ⋯ OC hydrogen bonds, the SH group being probably bound to the oxygen of an adjacent molecule. For CCl4 solutions, an intramolecular hydrogen bond NH ⋯ S is observed for the first compound only, corresponding to the formation of a five-membered ring.

Etude spectroscopique de derives mercuriques d'amides thiols: Partie IV. Spectres de vibration et structure des complexes CH3NHCOCH2− SHgCH3, CH3NHCOCH2CH2SHgCH3 et CH3CONHCH2CH2SHgCH3

Abstract The vibrational spectra of CH 3 NHCOCH 2 SHgCH 3 , CH 3 NHCOCH 2 CH 2 SHgCH 3 and CH 3 CONHCH 2 CH 2 SHgCH 3 have been analyzed. Mercury in the methylmercury group is covalently bonded to one sulphur atom. A preliminary study of CH 3 NHCOCH 2 CH 2 SHgCH 3 by X-ray diffraction revealed a five-atom ring with weak intramolecular bonding Hg·O. In CH 3 NHCOCH 2 CH 2 SHgCH 3 , Hg·O or Hg· Nbonding leads to an internal chelate with six atoms. These rings also exist in solution in acetonitrile and D 2 O. In the third complex, the existence of such chelates is doubtful.