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 p-p stacking and ion-p 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 p-p stacking and ion-p 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 p-p stacking and cation-p interactions reinforce each other in the ion-s-triazine-benzene triads while an opposite trend is obtained in the presence of anion-p interactions. On the other hand, contrary to cation-p interactions, p-p stacking and anion-p interactions are strengthened in the ion-s-triazine-hexafluorobenzene triads where both interactions coexist. These results indicate that the cooperative and synergistic effects between p-p stacking and ion-p interactions mainly depend on the nature of aromatic ring. Compared to ion-p interactions, it is also found that the p-p stacking is mostly affected by simultaneous presence of both interactions.