Modulating intramolecular P···N pnictogen interactions.

Area of Science:

• Computational Chemistry
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Pnictogen bonds are crucial non-covalent interactions.
• Understanding these bonds is key to designing novel molecular systems.
• Phosphinonaphthalenamine derivatives serve as model systems for studying pnictogen bonding.

Purpose of the Study:

• To computationally investigate intramolecular pnictogen bonds in 8-phosphinonaphthalen-1-amine derivatives.
• To determine the effect of substitutions on the P···N bond strength.
• To analyze structural, geometric, and electronic properties influencing pnictogen bond interactions.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Analysis of structural and geometric parameters.
• Calculation of interaction energies and electronic properties (e.g., electron density at bond critical points).

Main Results:

• Substitutions with electron-withdrawing groups on the Lewis acid moiety (PX2) strengthen the P···N pnictogen bond.
• Substitutions on the Lewis base moiety (NX2) result in weaker P···N interactions compared to PX2 substitutions.
• All substitutions enhance pnictogen bonds compared to the parent 1-NH2, 8-PH2 system.

Conclusions:

• The strength of intramolecular pnictogen bonds is tunable via chemical substitution.
• Electron-withdrawing groups on the Lewis acid are more effective in strengthening P···N bonds.
• These findings provide insights into the design of molecules with tailored non-covalent interactions.