Theoretical study on the interaction of the ammonium cation with decamethylcucurbit[5]uril

By using quantum mechanical density functional theory (DFT) calculations, the most probable structure of the decamethylcucurbit[5]uril–NH 4 + cationic complex species was derived. In this complex, the ammonium cation NH 4 + is bound by one linear hydrogen bond and two bifurcated hydrogen bonds to the five carbonyl oxygens of the parent macrocyclic receptor. The interaction energy of the resulting cationic complex was found to be −372.0 kJ mol −1 , which confirms the formation of this complex species. Graphical abstract