The protonation (m* and pKBH+) and thermodynamic (DeltaG0, DeltaH0, DeltaS0) parameters of ionization of four thioamides RCSNMe2 (R = Me, Et, i-Pr, t-Bu) have been determined in aqueous sulfuric acid in the 25-60°C temperature range with a UV technique. The title compounds are relatively strong bases; 100% protonation is reached in 47% H2SO4. Their solvation is lower than for primary thioamides and sulfides, as indicated by the higher values of m*, and close to the range of carbon bases. Base strengths are discussed in terms of the competition between internal and external stabilization.
THERMODYNAMICS OF PROTONATION OF N,N-DIMETHYLTHIOAMIDES IN AQUEOUS SULFURIC-ACID
BAGNO, ALESSANDRO;SCORRANO, GIANFRANCO
1990
Abstract
The protonation (m* and pKBH+) and thermodynamic (DeltaG0, DeltaH0, DeltaS0) parameters of ionization of four thioamides RCSNMe2 (R = Me, Et, i-Pr, t-Bu) have been determined in aqueous sulfuric acid in the 25-60°C temperature range with a UV technique. The title compounds are relatively strong bases; 100% protonation is reached in 47% H2SO4. Their solvation is lower than for primary thioamides and sulfides, as indicated by the higher values of m*, and close to the range of carbon bases. Base strengths are discussed in terms of the competition between internal and external stabilization.File in questo prodotto:
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