A theoretical study on ascorbic acid dissociation in water clusters.

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Biochemistry

Background:

• Ascorbic acid (Vitamin C) is a vital biomolecule with known dissociation in aqueous solutions.
• Understanding its dissociation behavior is crucial for various chemical and biological applications.
• Previous studies have explored this phenomenon, but detailed computational insights into the proton transfer mechanism are valuable.

Purpose of the Study:

• To investigate the dissociation of ascorbic acid in water using a theoretical cluster model approach.
• To calculate the thermodynamic and kinetic characteristics of proton transfer from ascorbic acid to water clusters.
• To determine the equilibrium constants (pK a ) for the dissociation processes.

Main Methods:

• Employed Density Functional Theory (DFT) with B3LYP, M06, and wB97XD functionals.
• Utilized the 6-311++G(d,p) basis set for all calculations.
• Incorporated continuum solvent models to simulate the aqueous environment.

Main Results:

• Calculated thermodynamic and kinetic parameters for proton transfer from ascorbic acid to water clusters.
• Determined equilibrium constants (pK a ) for the dissociation processes.
• DFT calculations, when combined with continuum solvent models, yielded results consistent with experimental data for ascorbic acid's dissociation constant.

Conclusions:

• The study successfully modeled the dissociation of ascorbic acid in water using DFT.
• The computational approach provides accurate predictions of the dissociation constant, validating the chosen theoretical methods.
• This research offers a deeper understanding of the molecular mechanisms governing ascorbic acid's behavior in aqueous solutions.