Bambus[6]uril as a novel example of a ditopic ion-pair molecular receptor for sodium iodide

By using quantum mechanical DFT calculations, the most probable structure of the bambus[6]uril-Na+I- electroneutral complex species was derived. In this complex with a plane of symmetry, the considered anion I-, included in the macrocyclic cavity, is bound by 12 weak hydrogen bonds between methine hydrogen atoms on the convex face of glycoluril units and the I- anion, while the sodium cation Na+ interacts only with two carbonyl oxygen atoms of the parent macrocyclic receptor. The interaction energy of the resulting complex, involving the Boys-Bernardi counterpoise corrections of the basis set superposition error, was found to be -593.8 kJ mol(-1).