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

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 ···Mg 2+ > π ···Ca 2+ > 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.