Strong Pancake 2e/12c Bond in π-Stacking Phenalenyl Derivatives Avoiding Bond Conversion

Area of Science:

• Organic Chemistry
• Computational Chemistry
• Materials Science

Background:

• Phenalenyl dimers exhibit unique 2-electron/12-carbon (2e/12c) bonding.
• The conversion of this 2e/12c bond to a carbon-carbon single bond is of recent interest.
• Understanding the factors influencing this bond conversion is crucial for designing novel materials.

Purpose of the Study:

• To theoretically investigate the 2e/12c bond in π-stacking phenalenyl derivatives.
• To elucidate the origin of the unusual bond conversion in these systems.
• To explore the impact of heteroatom substitution on bond stability and conversion.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• A series of π-stacking phenalenyl derivatives were theoretically investigated.
• Thermodynamic and dynamic aspects of bond conversion were analyzed.

Main Results:

• Bond conversion in unsubstituted phenalenyl dimers occurs readily at room temperature.
• Heteroatom substitution (Boron, Nitrogen) significantly stabilizes the 2e/12c bond.
• Charge transfer character enhances the stability of the 2e/12c bond in hetero adducts.
• Phosphorus substitution introduces Lewis acid-base interactions, further stabilizing the bond.

Conclusions:

• The 2e/12c bond in phenalenyl systems exhibits dynamic and thermodynamic conversion potential.
• Heteroatom substitution, particularly with nitrogen and phosphorus, hinders this conversion due to enhanced bond stabilization.
• Charge transfer and Lewis acid-base interactions are key factors governing the stability and reactivity of these unusual bonds.