Halogen and Hydrogen Bonding in Halogenabenzene/NH₃ Complexes Compared Using Next-Generation QTAIM

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Molecular Interactions

Background:

• Hydrogen and halogen bonding are crucial non-covalent interactions.
• Understanding their competition is key to designing novel materials and catalysts.
• Relativistic effects become significant for heavier halogens.

Purpose of the Study:

• To investigate the interplay between hydrogen and halogen bonding in (Y = Br, I, At)/halogenabenzene/NH3 complexes.
• To compare the efficacy of next-generation QTAIM with conventional QTAIM.
• To evaluate the impact of relativistic effects on these interactions.

Main Methods:

• Application of next-generation Quantum Theory of Atoms in Molecules (QTAIM).
• Utilizing the SR-ZORA Hamiltonian and effective core potentials (ECPs) to model relativistic effects.
• Analysis of 3-D bond paths using the bond-path framework set B.

Main Results:

• Next-generation QTAIM demonstrated superior responsiveness compared to conventional QTAIM.
• Subtle details of the hydrogen vs. halogen bonding competition were elucidated.
• The SR-ZORA method reduced or eliminated spurious features in the analysis.

Conclusions:

• Next-generation QTAIM is a powerful tool for detailed analysis of competing non-covalent interactions.
• Relativistic effects significantly influence the observed bonding characteristics.
• The study highlights the mixed chemical character of these complexes.