Selective Separation of Polyaromatic Hydrocarbons by Phase Transfer of Coordination Cages

Abstract

Here we report a new supramolecular strategy for the selective separation of specific polycyclic aromatic hydrocarbons (PAHs) from mixtures. The use of a triethylene glycol-functionalized formylpyridine subcomponent allowed the construction of an Fe^II₄L₄ tetrahedron <b>1</b> that was capable of transferring between water and nitromethane layers, driven by anion metathesis. Cage <b>1</b> selectively encapsulated coronene from among a mixture of eight different types of PAHs in nitromethane, bringing it into a new nitromethane phase by transiting through an intermediate water phase. The bound coronene was released from <b>1</b> upon addition of benzene, and both the cage and the purified coronene could be separated via further phase separation.