Does Oxygen Feature Chalcogen Bonding?

Area of Science:

• Computational chemistry
• Quantum chemistry
• Molecular interactions

Background:

• A σ-hole is an electron-deficient region on an atom involved in a covalent bond.
• Chalcogen bonding typically involves heavier elements in Group 16.
• The role of oxygen in chalcogen bonding is not well-established.

Purpose of the Study:

• To investigate the existence and nature of σ-holes on covalently bound oxygen atoms.
• To explore the potential of oxygen to form chalcogen bonds.
• To challenge the prevailing view that oxygen does not participate in chalcogen bonding.

Main Methods:

• Utilizing second-order Møller-Plesset perturbation theory (MP2) for electronic structure calculations.
• Employing Dunning's all-electron correlation consistent basis set (aug-cc-pVTZ).
• Analyzing 21 prototypical monomer molecules and exemplar 1:1 binary complexes with Lewis bases.

Main Results:

• Covalently bound oxygen atoms can exhibit positive or negative σ-holes.
• Oxygen-centered positive σ-holes facilitate chalcogen bonding interactions with Lewis bases.
• Weakly bound interactions were observed in binary complexes, supporting oxygen's role in chalcogen bonding.

Conclusions:

• Oxygen atoms can form chalcogen bonds, contrary to common assumptions.
• The presence of a positive σ-hole on oxygen is key to this interaction.
• This finding expands the scope of known chalcogen bonding systems.