Bambus[6]uril as a novel macrocyclic receptor for the cyanide anion

By using quantum mechanical DFT calculations, the most probable structure of the bambus[6]uril·CN− anionic complex species was derived. In this complex having C3 symmetry, the considered anion CN−, included in the macrocyclic cavity, is bound by 12 weak hydrogen bonds between methine hydrogen atoms on the convex face of glycoluril units of the parent macrocyclic receptor and the anion CN−. The interaction energy of the resulting complex, involving the Boys–Bernardi counterpoise corrections of the basis set superposition error, was found to be −324.3 kJ mol−1, which confirms the formation of the mentioned anionic complex.