Ligand exchange among iodine(I) complexes

A detailed investigation of ligand exchange between iodine(I) ions in [N⋯I⋯N]⁺ halogen-bonded complexes is presented. Ligand exchange reactions were conducted to successfully confirm whether iodine(I) complex formation, via the classical [N⋯Ag⋯N]⁺ to [N⋯I⋯N]⁺ cation exchange reaction from their analogous Ag⁺ complexes, could be determined solely by using ¹H NMR spectroscopy. In instances where the formation of the iodine(I) complex was unclear or in low yield by the traditional cation exchange reaction, a ligand exchange reaction was used to form the desired iodine(I) complexes in a quantitative manner. Mixing two homoleptic [N⋯I⋯N]⁺ iodine(I) complexes in 1 : 1 ratio was found to undergo a statistical ligand exchange, with ¹H NMR studies showing that the preferred formation of the relative heteroleptic [N₁⋯I⋯N₂]⁺ complexes increases with greater differences in the Lewis basicities of two XB acceptors of the complexes involved.