Structural discrimination of double-walled carbon nanotubes by chiral diporphyrin nanocalipers

Abstract

In this contribution, we demonstrate the separation of double-walled carbon nanotubes (DWNTs) by host–guest methodology. New chiral diporphyrin nanocalipers with a longer spacer (∼1.9 nm) consisting of carbazole–pyrene–carbazole are rationally designed as a host on the basis of the previous chiral diporphyrin nanocalipers with carbazole–anthracene–carbazole spacer (∼1.4 nm). The chiral nanocalipers are found to recognize the diameter of DWNTs to make diameter distribution much narrower. In addition, the extracted carbon nanotubes (CNTs) exhibited circular dichroism (CD) after removal of the chiral nanocalipers and dissolution in water in the presence of achiral surfactant.