Selective recognition and enrichment of C 70 over C 60 using an anthracene-based nanotube.

Selective recognition and enrichment of fullerenes ( e.g. , C 60 and C 70 ) remains challenging due to the same diameter and geometrical similarity. Herein, we report a hexagonal anthracene-based nanotube (1) through a one-pot Suzuki-Miyaura cross-coupling reaction. With anthracene-based side walls and pyridine linkers, 1 features a nano-scale tubular cavity measuring 1.2 nm in diameter and 0.9 nm in depth, along with pH-responsive properties. Interestingly, the electron-rich 1 shows high binding affinity ( K a ≈ 10 6 M -1 ) and selectivity ( K s ≈ 140) to C 70 over C 60 in toluene, resulting from their different contribution of π-π interactions with the host. The protonation of 1 simultaneously alters the electronic properties within the nanotube, resulting in the release of the fullerene guests. Lastly, the selective recognition and pH stimuli-responsive properties of the nanotube have been utilized to enrich C 70 from its low-content mixtures of fullerenes in chloroform.