Study on the interaction between dinaphthosulfide-substituted macrocyclic diamides and some metal ions: experimental measurements vs. quantum mechanical calculations

Abstract

Complexation properties of dinaphthosulfide-substituted macrocyclic diamides 1 and 2 with some metal cations that have been obtained by conductometric method are described with quantum mechanics calculations. To do this, the most stable structures of ligands, Hg2+-ligand complexes, ligand-MeOH and ClO4−–MeOH are optimized at HF/Lanl2dz level of theory and the most important interactions are analyzed by atoms in molecules (AIM) theory. These calculations predict the existence of strong interaction between Hg2+ cation and ligands 1 and 2, particularly, S–Hg2+ interaction. The different conductometric behaviors of complexation of ligands 1 and 2 with metal ions are interpreted on the basis of the calculated intramolecular hydrogen bonds in ligands and intermolecular hydrogen bonds between ligands and methanol as a solvent and perchlorate as a counter ion. In addition, binding energies between Hg2+ and ligands are also calculated by HF/Lanl2dz level of theory. Results show that all theoretical predictions are in line agreement with the experimental data.