Comprehensive Theoretical Study of Interactions between Ag⁺ and Polycyclic Aromatic Hydrocarbons

Area of Science:

• Computational Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Understanding metal-ligand interactions is crucial for designing new materials and catalysts.
• Silver(I) cations are known to interact with various π-systems, but a systematic theoretical analysis is lacking.
• The role of ligand structure in dictating bonding characteristics requires further investigation.

Purpose of the Study:

• To conduct a comprehensive theoretical study on the bonding nature and energetics of Ag(I) cation interactions with diverse π-ligands.
• To elucidate the contributions of ionic and covalent interactions to the overall bonding.
• To investigate the factors influencing the metal-to-ligand charge transfer and coordination modes.

Main Methods:

• Employed two complementary energy decomposition analysis (EDA) schemes: Natural Bond Orbital-Natural Energy Decomposition Analysis (NBO-NEDA) and Absolute Electron Density Analysis-Natural Orbitals for Chemical Valence (EDA-NOCV).
• Investigated a wide range of π-ligands, including ethylene, benzene, polycyclic aromatic hydrocarbons (PAHs), and C60 fullerene.
• Analyzed the orbital contributions, specifically ligand-to-metal (L→M) and metal-to-ligand (M→L) charge transfer.

Main Results:

• The bonding between Ag(I) and most π-ligands is predominantly ionic, with the exception of C60 fullerene where covalent interactions are strongest.
• Ligand-to-metal (L→M) charge transfer is a significant and consistent component across all systems.
• Metal-to-ligand (M→L) interactions vary based on the ligand's topology and aromaticity, influencing the coordination mode (e.g., η2 vs. η1) in PAHs.

Conclusions:

• Reliable characterization of Ag(I)-π-ligand interactions necessitates the use of multiple theoretical approaches.
• The bonding and coordination behavior are highly dependent on the electronic and structural properties of the π-ligand.
• This study provides fundamental insights into the complex interplay of factors governing late transition metal cation interactions with unsaturated hydrocarbons.