High-order layered self-assembled multicavity metal–-organic capsules and anti-cooperative host–multi-guest chemistry

Abstract

The construction and application of metal–organic cages with accessible internal cavities have witnessed rapid development, however, the precise synthesis of complex metal–organic capsules with multiple cavities and achievement of multi-guest encapsulation, and further in-depth comprehension of host–multi-guest recognition remain a great challenge. Just like building LEGO blocks, herein, we have constructed a series of high-order layered metal–organic architectures of generation n (n = 1/2/3/4 is also the number of cavities) by multi-component coordination-driven self-assembly using porphyrin-containing tetrapodal ligands (like plates), multiple parallel-podal ligands (like clamps) and metal ions (like nodes). Importantly, these high-order assembled structures possessed different numbers of rigid and separate cavities formed by overlapped porphyrin planes with specific gaps. The host–guest experiments and convincing characterization proved that these capsules G2–G4 could serve as host structures to achieve multi-guest recognition and unprecedentedly encapsulate up to four C₆₀ molecules. More interestingly, these capsules revealed negative cooperation behavior in the process of multi-guest recognition, which provides a new platform to further study complicated host–multi-guest interaction in the field of supramolecular chemistry.