Microsolvation versus Encapsulation in Mono, Di, and Trivalent Cations

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Chemical Physics

Background:

• Water clusters are fundamental models for solvation.
• Cation solvation influences water structure and hydrogen bonding.
• Understanding these interactions is key to chemical processes.

Purpose of the Study:

• To investigate the effect of formal charge on water cavity stability and bonding.
• To analyze how cations of varying charge density interact with water clusters.
• To characterize the resulting cluster structures and bonding mechanisms.

Main Methods:

• Simulations of [X(H2O)20]q+ clusters with mono-, di-, and trivalent cations.
• High-level electronic structure calculations using CCSD(T)-DLPNO.
• Analysis of bonding via Quantum Theory of Atoms in Molecules, Natural Bond Orbitals, and non-covalent surfaces.

Main Results:

• Cation presence strengthens water-water hydrogen bonds, enhancing cooperative effects.
• Cations with lower charge density favor approximate encapsulation within the water cavity.
• Cations with higher charge density prefer microsolvation, causing significant cavity deformation.

Conclusions:

• Formal charge is a critical factor determining cation solvation structure in water clusters.
• The interplay between cation charge density and water network dictates encapsulation versus microsolvation.
• These findings provide insights into ion-water interactions and solvent effects.