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Ab Initio Molecular Dynamics Study of the Keto–Enol Tautomerism of Acetone in Solution
Author(s) -
Cucinotta Clotilde S.,
Ruini Alice,
Catellani Alessandra,
Stirling András
Publication year - 2006
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600007
Subject(s) - tautomer , chemistry , enol , keto–enol tautomerism , intramolecular force , computational chemistry , metadynamics , ab initio , ab initio quantum chemistry methods , hydrogen atom , photochemistry , molecular dynamics , molecule , organic chemistry , catalysis , alkyl
We have studied the keto–enol interconversion of acetone to understand the mechanism of tautomerism relevant to numerous organic and biochemical processes. Applying the ab initio metadynamics method, we simulated the keto–enol isomerism both in the gas phase and in the presence of water. For the gas‐phase intramolecular mechanism we show that no other hydrogen‐transfer reactions can compete with the simple keto–enol tautomerism. We obtain an intermolecular mechanism and remarkable participation of water when acetone is solvated by neutral water. The simulations reveal that C deprotonation is the kinetic bottleneck of the keto–enol transformation, in agreement with experimental observations. The most interesting finding is the formation of short H‐bonded chains of water molecules that provide the route for proton transfer from the carbon to the oxygen atom of acetone. The mechanistic picture that emerged from the present study involves proton migration and emphasizes the importance of active solvent participation in tautomeric interconversion.