A comparative study of cooperative effects between the intramolecular hydrogen bond and cation···π interaction in various complexes of ortho-aminobenzaldehyde with its thio and seleno analogous

Abstract

In the present study, a comparative study of cooperative effect between the intramolecular hydrogen bond (IMHB) and cation···π interactions for the first time in some complexes of ortho-aminobenzaldehyde with its thio and seleno analogues at the M062X/6-311++G(d, p) level of theory has been carried out. The energetic, geometric, spectroscopic, topologic and molecular orbital descriptors were used to evaluate the strength of the IMHB and cation···π interactions in the benchmark systems. Based on the energetic results, for the double-charge cations, the coexistence of these non-covalent interactions increases the strength of the cation···π, while for the mono-charge cations the reverse process is observed. However, for both type of the cations (mono- and double charges), this coupling leads to a stronger IMHB. In contrast to the energetic conclusions, the results of the other descriptors indicated that the coupling simultaneously strengthens both of the interactions . On the other hand, the harmonic oscillator model of aromaticity was applied to evaluate the significance of π-electron delocalization (π-ED) within the RAHB unit and aromaticity of benzene ring in the title complexes. These results revealed that the mentioned coupling decreased the π-ED and aromaticity. Furthermore, the change in strengths of the IMHB and cation···π interactions and also the significant of π-ED and aromaticity can be arranged in π···Mg2+ > π···Ca2+ > π···Li+> π···K+ > π···Na+ order. Finally, the sulfur and selenium atoms replaced instead of oxygen to explore their influences on the nature of IMHB, cation···π, π-ED and aromaticity.