A regioselectively bis(thiourea)-substituted dibenzo-diaza-30-crown-10: a new strategy for the development of multi-site receptors

Due to our interest in the functionalization of dibenzo-30-crown-10 moiety, a regioselectively dinitro-derived congener 1 was conveniently synthesized. The availability of the compound as a building block to develop new molecular systems allowed us to prepare a multi-site receptor 3, desirable for cooperative complexation of cationic and anionic species in an induced fit fashion. Indeed, K+ accommodated in the crowned cavity did not only tune the conformation to bind anions but also associated in the anion binding efficiently.