How Many Pnicogen Bonds can be Formed to a Central Atom Simultaneously?

Area of Science:

• Computational Chemistry
• Inorganic Chemistry
• Supramolecular Chemistry

Background:

• Pnicogen bonds (ZBs) are non-covalent interactions involving pnicogen elements (Group 15).
• Understanding ZB strength and coordination number is crucial for designing novel materials and predicting reactivity.

Purpose of the Study:

• To investigate the strength and number of pnicogen bonds (ZBs) formed by central ZF3 molecules (Z = P, As, Sb, Bi).
• To explore the influence of both the pnicogen atom and the nucleophile on the ZB characteristics.

Main Methods:

• Computational modeling was used to simulate interactions between ZF3 molecules and various nucleophiles (NCH, NH3, NC-).
• Analysis focused on bond lengths, strengths, and coordination numbers.

Main Results:

• Pnicogen bond strength increases with heavier pnicogen atoms (P < As < Sb < Bi) and stronger nucleophiles (NCH < NH3 < NC-).
• The maximum number of ZBs varies: PF3 and AsF3 form one with CN-, SbF3 and BiF3 form two weakly with anions.
• NH3 can form up to three ZBs, while BiF3 can accommodate four ZBs with NH3, though the fourth is weaker and relies on secondary interactions.

Conclusions:

• The study quantifies the factors governing pnicogen bond formation and coordination.
• Results provide insights into the directional bonding capabilities of pnicogen compounds for potential applications in materials science.