Formation of ternary complexes between a macrotricyclic host and hetero-guest pairs: an acid-base controlled selective complexation process.

A triptycene-based cylindrical macrotricyclic host can include diquat and electron-rich aromatics simultaneously to form stable ternary complexes, which is stabilized not only by a charge-transfer (CT) interaction between electron-rich and electron-deficient guests but also by the face to face pi-stacking interactions between the host and the guests. Moreover, a selective complexation process between a ternary complex containing benzidine and a binary complex can be effectively controlled by the use of acid and base.