Effect of stepwise microhydration on the guanidinium···π interaction

Area of Science:

• Biophysical Chemistry
• Computational Chemistry
• Molecular Interactions

Background:

• Aromatic amino acids are crucial in protein structure and function.
• Guanidinium cation is a key functional group in biological systems.
• Understanding cation-aromatic interactions is vital for molecular recognition.

Purpose of the Study:

• To investigate the interaction between microhydrated guanidinium cation and aromatic moieties.
• To elucidate the role of water in modulating these interactions.
• To characterize the binding modes and strengths.

Main Methods:

• Computational chemistry methods were employed.
• Analysis of stable minima for hydrated and non-hydrated complexes.
• Evaluation of interaction energies and structural patterns.

Main Results:

• Non-hydrated complexes show stable structures with N-H···π hydrogen bonds.
• Interaction strength increases from benzene to phenol to indole.
• Water molecules introduce complexity, forming diverse stable structures with varied hydrogen bonds.
• Cation···π contact strength dictates differences in stability.

Conclusions:

• Water significantly influences guanidinium-aromatic interactions.
• Hydrogen bonding networks involving water create multiple stable configurations.
• The strength of cation···π interactions is a key determinant of complex stability.