Influence of three-body effects on halogen bonding

Area of Science:

• Computational chemistry
• Chemical physics
• Molecular interactions

Background:

• Noncovalent interactions are crucial in chemistry and biology.
• Understanding three-body effects is essential for accurate molecular modeling.
• Existing datasets may not fully capture complex noncovalent interactions.

Purpose of the Study:

• To create a new benchmark dataset (3BXB) for three-body noncovalent complexes.
• To investigate the physical origins of binding and cooperativity in these complexes.
• To evaluate computational methods for predicting interaction energies.

Main Methods:

• Construction of the 3BXB dataset by combining existing complexes with a third interacting partner (H2O or CH4).
• High-level ab initio calculations (CCSD(T)) for reference interaction energies.
• Symmetry-Adapted Perturbation Theory (SAPT) based energy decomposition analysis.

Main Results:

• Two-body attractions are dominated by electrostatics or dispersion.
• Three-body effects are primarily driven by induction, which can be attractive or repulsive.
• Wavefunction-based SAPT methods with corrections accurately predict interaction energies.

Conclusions:

• The 3BXB dataset provides valuable insights into three-body noncovalent interactions.
• Induction plays a key role in the cooperativity of these complexes.
• Accurate prediction of interaction energies is achievable with advanced computational methods.