Strategies for Enhancing Macrocyclic Host-Guest Properties

ConspectusMacrocyclic hosts stand as a cornerstone within supramolecular chemistry, whereas enhancing the host-guest performance of macrocyclic hosts is pivotal for advancing their applications in cutting-edge research fields. Benefiting from their unique cyclic cavity structures and precise molecular recognition capabilities, macrocyclic hosts show great potential in diverse interdisciplinary areas. However, further improving their host-guest recognition and assembly performance remains a key challenge for developing high-performance macrocycle-based materials. To address this issue, our group has carried out systematic and in-depth studies and developed a series of effective strategies to enhance macrocyclic host-guest properties, which have been effectively applied in molecular recognition and the fabrication of functional supramolecular materials.In this Account, we systematically summarize and classify the strategies for improving the host-guest recognition and assembly performance of macrocyclic hosts developed by our group into six categories. Representative work from other researchers is also appropriately introduced. These six strategies are efficient and versatile, and they can significantly boost macrocyclic host-guest properties: (1) synergy between macrocycles and functional groups; (2) multimacrocycle synergy; (3) construction of networked frameworks via macrocycle-guest assembly; (4) macrocycle-metal coordination for arrays and frameworks; (5) tailored development of novel functional macrocycles; and (6) fused macrocyclic systems. Through the above six strategies, we have significantly improved the host-guest properties, recognition selectivity, and sensing sensitivity of macrocyclic hosts and effectively expanded their application potential. Among these, the synergistic effect between macrocycles and functional groups significantly enhances the recognition capability, selectivity, and sensitivity toward targeted guest molecules. The assembly of macrocycles with appropriate guests allows the construction of supramolecular polymeric networks and framework architectures, endowing macrocycles with promising applications in molecular sensing, capture, and separation. Furthermore, the rational design and synthesis of new macrocycles offers effective strategies for the precise recognition and separation of specific guests. The construction of multimacrocyclic systems extends the dimensionality of macrocyclic assembly, and their applications in hierarchical and orthogonal assembly further enrich the assembly behavior and host-guest performance of macrocycles. The unique advantages of each strategy are discussed in detail with typical examples to demonstrate their effectiveness and generality. Furthermore, we highlight the application potentials of these strategies in various fields, including enhanced sensing, catalysis, adsorption and separation, modulated luminescence, bioimaging, and so on. Finally, we provide perspectives on future trends and remaining challenges, aiming to establish a theoretical basis for designing high-performance macrocycle-based supramolecular advanced materials.