Tautomeric Equilibrium in Condensed Phases.

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Biophysical Chemistry

Background:

• Tautomeric equilibrium is crucial for chemical and biological processes.
• Proton transfer in aqueous solutions is complex due to water-ion interactions.
• Standard enhanced sampling methods can struggle with proton dynamics in condensed systems.

Purpose of the Study:

• To investigate tautomeric equilibrium in aqueous glycine and acetone using ab initio molecular dynamics.
• To apply a novel collective variable (CV) approach for studying proton transfer reactions.
• To demonstrate the method's ability to capture complex dynamics without prior assumptions.

Main Methods:

• Ab initio molecular dynamics (MD) simulations.
• Metadynamics for accelerated proton migration.
• A recently developed set of collective variables (CVs) for proton transfer reactions.

Main Results:

• Observed complex reaction pathways and non-trivial conversion dynamics for glycine and acetone in water.
• Successfully modeled tautomeric interconversion without prior knowledge of dissociation pathways.
• Validated the generality and applicability of the CV-based method for proton transfer.

Conclusions:

• The developed CV approach is effective for studying tautomeric reactions in complex systems.
• Even simple molecules like glycine and acetone exhibit intricate proton dynamics in water.
• This method provides a robust tool for investigating proton dissociation and tautomerization.