Changing the Hydrophobic MOF Pores through Encapsulating Fullerene C₆₀ and Metallofullerene Sc₃C₂@C₈₀

We report that the encapsulation of fullerene or metallofullerene can greatly change the hydrophobic property of pores for metal-organic frameworks (MOFs). The adsorption capacities for several aromatic molecules (toluene, benzene, xylene, and chlorobenzene) were raised after incorporating C₆₀ into MOF-177. In addition, paramagnetic metallofullerene Sc₃C₂@C₈₀ with an electron spin was encapsulated into the pores of two kinds of MOFs (MOF-177 and MOF-180) filling with toluene solvent. It is found that Sc₃C₂@C₈₀ electron spin can sense the different pore sizes of MOFs as shown by its varied electron paramagnetic resonance signals, which are affected by the different confinement effects in space. The filling toluene solvent within MOFs plays an important role in steering the spin relaxation of Sc₃C₂@C₈₀@MOFs through lubricating the motion of Sc₃C₂@C₈₀ balls. These results revealed that metallofullerene Sc₃C₂@C₈₀ can act as a spin probe to sensitively detect the pore environment of MOFs. Moreover, the fullerenes and metallofullerenes can act as additives to tune the oleophilic property of MOF pores, which will promote the application of this kind of complex materials as a new adsorbing and separating material.