Very long-range effects: cooperativity between anion-pi and hydrogen-bonding interactions

Area of Science:

• Supramolecular Chemistry
• Computational Chemistry
• Chemical Physics

Background:

• Non-covalent interactions are crucial in molecular recognition and self-assembly.
• Aromatic rings participate in various interactions, including anion-pi and hydrogen bonding.
• Understanding the interplay of these forces is key to designing functional molecular systems.

Purpose of the Study:

• To investigate the cooperative effects between anion-pi and hydrogen bonding interactions.
• To determine the distance over which these cooperative effects are significant.
• To characterize the nature of these interactions using computational methods.

Main Methods:

• Ab initio calculations were employed to compute the energetic and geometric features of molecular complexes.
• Analysis of energetic and geometric parameters to assess interaction strength and cooperativity.
• Bader's theory of atoms-in-molecules was used to characterize charge density and interaction types.

Main Results:

• Significant cooperative effects were observed when anion-pi and hydrogen bonding coexist in molecular complexes.
• These cooperative effects were detected at distances up to approximately 11 Angstroms.
• Charge density analysis confirmed the strengthening or weakening of interactions based on electronic redistribution.

Conclusions:

• Anion-pi and hydrogen bonding interactions exhibit notable cooperativity, influencing molecular complex behavior.
• These combined interactions play a role in molecular systems over considerable distances.
• Computational analysis provides valuable insights into the nature and extent of these non-covalent interactions.