Erythronium Bonds: Noncovalent Interactions Involving Group 5 Elements as Electron-Density Acceptors

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Biochemistry

Background:

• Group 5 elements are known to form coordination bonds.
• Noncovalent interactions play crucial roles in molecular recognition and biological processes.
• Understanding novel bonding types is essential for advancing chemical and biological sciences.

Purpose of the Study:

• To identify and characterize a new type of noncovalent interaction involving group 5 elements.
• To differentiate this new interaction from traditional coordination bonds.
• To investigate the presence of this interaction in biological systems.

Main Methods:

• Analysis of the Cambridge Structural Database.
• Theoretical calculations including PBE0-D3/def2-TZVP level, atoms-in-molecules (AIM), and natural bond orbital (NBO) studies.
• Examination of X-ray structures of vanadate-dependent bromoperoxidases.

Main Results:

• Evidence for net attractive noncovalent interactions between group 5 elements and electron-rich atoms (neutral or anionic).
• These interactions exhibit characteristics of σ-hole bonding, distinguishing them from coordination bonds.
• The proposed term 'erythronium bond' is introduced for this interaction.
• The presence of these interactions confirmed in biological systems (vanadate-dependent bromoperoxidases).

Conclusions:

• A novel noncovalent interaction, the erythronium bond, has been identified and characterized.
• Erythronium bonds represent a distinct bonding paradigm compared to coordination bonds involving group 5 elements.
• These interactions are biologically relevant, as evidenced by their presence in enzymes.