Fahimeh Alirezapour - Department of Chemistry, Payame Noor University (PNU), P.O.Box ۱۹۳۹۵-۴۶۹۷, Tehran, Iran
Marziyeh Mohammadi - Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
Azadeh Khanmohammadi - Department of Chemistry, Payame Noor University (PNU), P.O.Box ۱۹۳۹۵-۴۶۹۷, Tehran, Iran

In the present study, the density functional theory (DFT) method has been used to investigate the interplay effects between cation–π and intramolecular hydrogen bond (IMHB) interactions in the complexes formed by the mesalazine and metal cations (Li+, Na+, K+, Be۲+, Mg۲+ and Ca۲+). The topological properties and the charge transfer values are estimated using the atoms in molecules (AIM) and natural bond orbital (NBO) analyses, respectively. The results indicate that the coupling simultaneously decreases the IMHB strength and increases the cation–π interaction. Our data also show that the strength of cation–π interactions enhances with increasing the charge-to-radius ratio of the cations, while the reverse results are observed for the IMHB interactions. Finally, the frontier molecular orbitals are applied to evaluate the conceptual DFT parameters such as energy gap, chemical hardness and electronic chemical potential of the complexes.

Cation˗π, Intramolecular hydrogen bond, DFT, aim, NBO