Tuning of the anion-π interaction

In this manuscript, we report an ab initio theoretical study (RI-MP2/aug-cc-pVDZ) that deals with the effect of having different electron acceptor molecules interacting with the aromatic moiety (s-triazine) on the anion-pi interaction strength. Depending on the type and number of interacting molecules, a wide range of complexation energies can be obtained, and therefore, a tuning of the interaction strength can be adjusted. In addition, cooperativity effects between the anion-pi and a variety of other noncovalent and convalent interactions are analyzed and compared. We have used Bader's theory of "atoms-in-molecules" to demonstrate that the electron density computed at the bond critical point that emerges upon complexation can be used not only as a measure of bond order but also as a measure of cooperativity and interplay between the noncovalent interactions that coexist in the same complex.