Carbohydrate-aromatic pi interactions: a test of density functionals and the DFT-D method.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Biomolecular Interactions

Background:

• Carbohydrate-pi interactions are crucial in biological systems.
• Accurate computational modeling of these interactions is essential for understanding molecular recognition.
• Density Functional Theory (DFT) is a widely used method for electronic structure calculations.

Purpose of the Study:

• To evaluate the performance of various DFT functionals for describing carbohydrate-pi interactions.
• To identify the most accurate DFT methods for modeling these non-covalent interactions.
• To compare DFT results against high-level ab initio calculations.

Main Methods:

• A database of interaction energies for representative carbohydrate-pi complexes was compiled using high-level ab initio methods.
• Eighteen different DFT functionals, including M05 and M06 families, were tested.
• The DFT-D method, incorporating empirical dispersion corrections, was also evaluated.

Main Results:

• The DFT-D method and M06 class of functionals demonstrated excellent performance in describing carbohydrate-pi interactions.
• Traditional functionals, such as B3LYP, exhibited poor accuracy.
• Calculated interaction energies for 23 sugar-aromatic complexes using DFT-D were compared with results from 18 functionals, confirming the superiority of M06.

Conclusions:

• The M06 functionals and DFT-D method are highly recommended for accurate calculations of carbohydrate-pi interactions.
• Traditional DFT functionals are less suitable for this type of non-covalent interaction.
• This study provides valuable guidance for selecting appropriate computational methods in carbohydrate-pi interaction research.