Guest‐Induced “Breathing‐Helical” Dynamic System of a Porphyrinic Metallo‐Organic Cage for Advanced Conformational Manipulation

Abstract

Host‐guest dynamic systems in coordination‐driven metallo‐organic cages have gained significant attentions since their promising applications in chiral separation, drug delivery, and catalytical fields. To maximize guest‐binding affinity, hosts adopting multiple conformations are widely investigated on their structural flexibility for guest accommodation. In this study, a novel metallo‐organic cage S with breathing inner cavity and freely twisted side chains was proposed. Single‐crystal X‐ray diffraction analyses depicted a characteristic “breathing‐helical” dynamic system on the semiflexible framework, which led to an unprecedent co‐crystallisation of racemic and symmetric conformations via the encapsulation locking of C70 guests. By taking advantages of the high binding affinity, selective extraction of C70 was realized. This research provides new ideas for the modification on the helicities of metallo‐organic cages, which could pave a new way for advanced conformational manipulation of supramolecular host systems.