Unraveling cation–cation “attraction” in argentophilic interaction in 2,2′-bipydine coordinated silver complex

The nature of argentophilic interaction in the 2,2'-bipyridine-coordinated silver complex, which manifests counterintuitive cation-cation "attraction," is attributed to ligand stacking and solvation effects in the present article. While charged closed-shell transition metal complexes aggregating spontaneously to form oligomers has long been observed experimentally, the interpretation of the nature of so-called metallophilicity is still ongoing. For the dimer [(2,2'-bpy)2Ag]22+, qualitative electrostatic potential, non-covalent interaction, atoms-in-molecules analyses, and quantitative energy decomposition analysis calculations indicate that the electrostatic repulsion between two like formal charges at silver centers can be overcome by long-range dispersion attraction and short-range electronic correlation from ligands. In addition, delocalizing the net charges on silvers over the whole ligands can decrease electrostatic repulsion of metal centers to stabilize oligomers. The vital role of the screening effect of solvent has also been realized in the bound binding of the title system. Overall, this research highlights the importance of ligand stacking to argentophilicity, while d10-d10 attraction of silver centers presents quite little contribution.