A theoretical study of glucose mutarotation in aqueous solution.

Area of Science:

• Carbohydrate Chemistry
• Physical Organic Chemistry
• Computational Chemistry

Background:

• Glucose mutarotation is a key reaction in carbohydrate chemistry.
• Existing models propose intramolecular or solvent-assisted proton transfer mechanisms.
• Experimental data suggests a solvent-assisted pathway is dominant.

Purpose of the Study:

• To computationally investigate and compare two proposed mechanisms for glucose mutarotation in aqueous solution.
• To elucidate the dominant reaction pathway for glucose anomerization.
• To provide theoretical support for experimental findings.

Main Methods:

• Quantum chemical calculations were employed to study reaction pathways.
• A polarizable continuum model (PCM) was used to simulate aqueous solution effects.
• Transition-state theory was applied to calculate reaction rate coefficients.
• Vibrational frequency analysis confirmed characterized structures.

Main Results:

• Both intramolecular and water-assisted proton transfer mechanisms were modeled.
• Calculated rate coefficients were compared between gas phase and aqueous solution simulations.
• The water-assisted mechanism in continuum solvent yielded results closest to experimental values.
• Theoretical structures were fully characterized.

Conclusions:

• The water-assisted proton transfer mechanism is favored in aqueous solution for glucose mutarotation.
• Computational modeling provides valuable insights into reaction mechanisms in solution.
• This study validates the importance of solvent effects in chemical reactions.