The pnictogen bond: a quantitative molecular orbital picture

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Chemical Bonding

Background:

• Pnictogen bonds are intermolecular interactions involving pnictogen elements (N, P, As, Sb).
• Understanding their strength and mechanism is key to predicting molecular behavior and designing new materials.

Purpose of the Study:

• To compute accurate trends in pnictogen-bond strength.
• To elucidate the bonding mechanism using advanced computational methods.

Main Methods:

• Relativistic density functional calculations (ZORA-M06/QZ4P).
• Quantitative Kohn-Sham molecular orbital (KS-MO) theory.
• Energy Decomposition Analysis (EDA) and Voronoi Deformation Density (VDD) analyses.

Main Results:

• Pnictogen bonds exhibit significant covalent character.
• Strong HOMO-LUMO interactions between the lone pair of A- and σ* of D3Pn drive the bond.
• Trends in pnictogen-bond strength were accurately computed.

Conclusions:

• The bonding mechanism of pnictogen bonds is comparable to hydrogen, halogen, and chalcogen bonds.
• Pnictogen bonds possess a substantial covalent component, influencing their stability and reactivity.