The role of nature of aromatic ring on cooperativity between π–π stacking and ion–π interactions: A computational study

In this manuscript, the role of nature of aromatic ring on cooperativity between π–π stacking and ion–π interactions is investigated in the cation–benzene–s-triazine, anion–hexafluorobenzene–s-triazine, ion–s-triazine–benzene and ion–s-triazine–hexafluorobenzene complexes at M06-2X/6–311++G(d,p) level of theory. The reinforcement of π–π stacking and ion–π interactions is confirmed in the cation–benzene–s-triazine and anion–hexafluorobenzene–s-triazine ternary complexes where both interactions exist concurrently. It is found that π–π stacking and cation–π interactions reinforce each other in the ion–s-triazine–benzene triads while an opposite trend is obtained in the presence of anion–π interactions. On the other hand, contrary to cation–π interactions, π–π stacking and anion–π interactions are strengthened in the ion–s-triazine–hexafluorobenzene triads where both interactions coexist. These results indicate that the cooperative and synergistic effects between π–π stacking and ion–π interactions mainly depend on the nature of aromatic ring. Compared to ion–π interactions, it is also found that the π–π stacking is mostly affected by simultaneous presence of both interactions.