Macrocycle-Dimer-Based Hydrogen-Bonded Networks for Capture of a Mustard Gas Simulant via Intra- and Intercavity Dual Cooperativity

Precise modulation and further enhancement of macrocyclic host-guest binding properties remain significant challenges. Herein, an intra- and intercavity cooperative strategy has been developed by rationally installing rigid arms at the macrocyclic periphery to disrupt their tight crystal packing, thereby generating additional inter-ring cavities. Based on this, A,A'-ortho-bis(pyridyl-hydrazone)-conjugated pillar[5]arene (o-PYP5) was synthesized. Unlike traditional macrocyclic hosts that rely solely on a single intrinsic cavity for guest encapsulation, o-PYP5 can self-assemble into hydrogen-bonded dimers, which further organize into a hydrogen-bonded dimer network crystal (HBDC) in the solid state, featuring both its intrinsic inner cavity and additional inter-ring cavities. The intra- and intercavity dual synergistic effect enhances the molar adsorption toward 2-chloroethyl ethyl sulfide (CEES), a mustard gas simulant, to twice that of EtP5.