The chalcogen bond: can it be formed by oxygen?

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Chemical Bonding

Background:

• Chalcogen bonds are typically associated with sulfur, selenium, and tellurium.
• Oxygen atoms in molecules were previously thought to be incapable of forming chalcogen bonds.

Purpose of the Study:

• To investigate the potential of oxygen atoms to form chalcogen bonds.
• To examine the interactions between oxygen difluoride (OF2) and various Lewis bases.

Main Methods:

• Density Functional Theory (DFT) calculations using the M06-2X functional.
• Ab initio first-principles calculations at the MP2 level of theory.
• Analysis using molecular electrostatic surface potential, Natural Bond Orbital (NBO) theory, and Quantum Theory of Atoms in Molecules (QTAIM).

Main Results:

• Oxygen difluoride (OF2) exhibits positive σ-holes along the F-O bond extensions.
• These σ-holes enable OF2 to participate in chalcogen bonding with Lewis bases.
• Calculations confirmed the stability of OF2-Lewis base complexes due to these interactions.

Conclusions:

• Oxygen atoms are capable of forming chalcogen bonds.
• The electrostatic surface potential model alone is insufficient for analyzing noncovalent interactions.
• Charge density topologies are crucial for a comprehensive understanding of chalcogen bonding involving oxygen.