ESI-MS estimation of the gas phase acidities of polyfunctional groups by the kinetic method: hydroxycinnamic acids.

摘要

The GAs of the different acidic groups of three hydroxycinnamic acids were estimated using the EKM. In the case of cinnamic acid the results could be accepted as definitive. Two different values of acidity were obtained for the two deprotonable groups of coumaric acid. The observed discrepancy between computational and experimental results will be analyzed. The results obtained for caffeic acid indicate the formation of a bidentate cluster. Anyway the acidity of this group and the carboxylic one were determined. The data will be recalculated by weighted orthogonal distance regression.