Related Experiment Video
Updated: Aug 7, 2026

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
Exploring intramolecular reactions in complex systems with metadynamics: the case of the malonate anions
Eliana Asciutto1, Celeste Sagui
1Center for High Performance Simulations and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA.
Abstract:
We have determined the optimized structures, relative energies and intramolecular reactions for two anionic forms of malonic acid, anion malonate(-1) (HO(2)CCH(2)CO(2)(-)) and malonate(-2) ((-)O(2)CCH(2)CO(2)(-)). For this purpose we employed accurate quantum chemistry calculations using second-order Möller-Plesset perturbation theory and Density Functional Theory with an aug'-cc-p-VTZ basis set to determine the structures and energies, and a novel metadynamics method based on Car-Parrinello molecular dynamics for the thermal reactions. For both malonates, we found new isomers (keto and enol structures) characterized by CO(2) rotations and intramolecular proton transfers. These proton transfers characterize the keto-enol tautomerism that takes place both in the monoanion and dianion. In all cases, the keto tautomer is the more stable configuration. The metadynamics method allows the system to explore the potential energy surface in a few picoseconds, crossing activation barriers of 20-50 kcal/mol.
Related Concept Videos
Intramolecular Aldol Reaction
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Radical Reactivity: Intramolecular vs Intermolecular
Loss of Carboxy Group as CO2: Decarboxylation of Malonic Acid Derivatives
Conjugate Addition of Enolates: Michael Addition
Formation of Complex Ions

