The modulation of proton transfer reactions by environmental effects has been investigated for the case of keto-enol isomerization of formamide. Formation of long-lived adducts with a single water mol. or of formamide dimers enhances the reaction rate and shifts the equil. towards the lactam form. The effect of bulk solvent on these adducts is small, whereas it further stabilizes the keto form of free formamide. Zero point and entropy effects on the thermodn. and kinetics of the reaction are generally negligible and do not modify the above general trend. Significant reaction rates are obtained well under the energy barrier due to tunneling. They are, however, smeared out when going from microcanonical to canonical ensembles
Direct Catalytic Effect anf Fine Modulation of Solvent in the Keto-Enol Isomerization of Amides
ADAMO, Carlo;MINICHINO, Camilla
1995-01-01
Abstract
The modulation of proton transfer reactions by environmental effects has been investigated for the case of keto-enol isomerization of formamide. Formation of long-lived adducts with a single water mol. or of formamide dimers enhances the reaction rate and shifts the equil. towards the lactam form. The effect of bulk solvent on these adducts is small, whereas it further stabilizes the keto form of free formamide. Zero point and entropy effects on the thermodn. and kinetics of the reaction are generally negligible and do not modify the above general trend. Significant reaction rates are obtained well under the energy barrier due to tunneling. They are, however, smeared out when going from microcanonical to canonical ensemblesI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
