Weak interactions between hypohalous acids and dimethylchalcogens.

Area of Science:

• Computational chemistry
• Molecular interactions
• Quantum chemistry

Background:

• Dimethylchalcogens (X(CH3)2) and hypohalous acids (YOH) are key chemical species.
• Understanding their complex formation is crucial for predicting chemical reactivity.

Purpose of the Study:

• To investigate the structures and stability of complexes formed between dimethylchalcogens and hypohalous acids.
• To analyze the nature and strength of intermolecular interactions, including hydrogen and halogen bonds.

Main Methods:

• Utilized the MP2/aug'-cc-pVTZ computational level for high-accuracy calculations.
• Employed Density Functional Theory for Symmetry Adapted Perturbation Theory (DFT-SAPT) to analyze interaction energy components.

Main Results:

• Identified five stable minimum energy structures, including hydrogen bonds (HB), halogen bonds (XB), and C-H···O contacts.
• Found strong halogen···chalcogen interactions (up to -49 kJ mol-1) in IOH and BrOH complexes, and stable hydrogen bonds (-27 to -34 kJ mol-1) with ClOH and FOH.
• Established linear correlations between molecular electrostatic potential (MEP) and interaction energies.

Conclusions:

• The study elucidates the preferred binding modes (HB vs. XB) based on the specific chalcogen and halogen involved.
• Electrostatic interactions predominantly drive complex formation, though dispersion and induction forces can be significant in certain cases.