Size-selective encapsulation of metallofullerenes by [12]Cycloparaphenylene and dissociation using metal-organic framework

The supramolecular complexes of metallofullerenes and carbon nanoring were constructed and their properties were studied. The size-selective encapsulation of metallofullerene Sc₃N@C₇₈, Sc₃N@C₈₀ and Sc₂C₂@C₈₂ by a carbon nanoring of [12]Cycloparaphenylene ([12]CPP) was found. Fluorescence spectral titration experiments showed the different quenching effect of matallofullerenes on photoluminance of [12]CPP. It was found that Sc₂C₂@C₈₂ has a stronger affinity to [12]CPP, and their supramolecular complex has a stronger host-guest interaction. Electrochemical results revealed that the redox potentials of encapsulated matallofullerenes are shifted compared to pristine species. Moreover, these supramolecular complexes can be dissociated using a metal-organic framework (MOF-177), which can only absorb the metallofullerene, leaving behind hollow [12]CPP. These results reveal the special supramolecular chemistry for metallofullerenes, [12]CPP nanoring, and porous MOF-177. In addition, the powerful attraction of porous MOF-177 for metallofullerene can break the host-guest interaction between metallofullerene and nanoring, which is applicable in separation.