Macrocycle-Integrated MOF Nanoarchitectures: Cooperative Active Sites from Pillararenes, Calixarenes, and Crown Ethers

Metal-organic frameworks (MOFs) offer crystalline porosity, modular structures, and tunable chemical environments, but they often lack the molecular recognition needed for highly selective adsorption, transport, and catalysis. Integrating macrocycles such as pillararenes, calixarenes, and crown ethers provides a route to macrocycle@MOF nanoarchitectures in which supramolecular cavities cooperate with framework pores, metal nodes, and linker functionalities. Calixarene-based MOFs create adaptive pockets for iodine capture, NO₂ sensing, and molecular separation; pillararene systems provide rigid, electron-rich channels for sieving, controlled release, and supramolecular docking; and crown-ether-functionalized MOFs enable selective ion transport, lithium sieving, and Sr²⁺/Cs⁺ remediation. Their function arises from coupled host-guest recognition, pore confinement, electrostatic complementarity, and active-site organization. Key challenges include pore blocking, synthetic complexity, structural disorder, incomplete active-site validation, and device integration. This review highlights design principles for converting macrocycle-integrated MOFs from proof-of-concept materials into practical recognition platforms for advanced catalysis, separations, sensing, remediation, energy technologies, and biomedical applications.