Tethered anthracene pair as molecular tweezers for post-production separation of single-walled carbon nanotubes

Highlights: • As-produced samples of SWNTs are metallic and semiconducting mixtures. • Metallic and semiconducting SWNTs can be separated via selective interactions. • Planar aromatic species selectively interact with metallic and semiconducting SWNTs. • Molecular tweezers of paired aromatic species are highly effective separation agents. • An appropriate molecular tweezers-solvent combination enables bulk separation. As-produced single-walled carbon nanotubes (SWNTs) are metallic and semiconducting mixtures. An anthracene mono-derivative with a long alkyl tail and a molecule with a tethered pair of anthracene species (bis-anthracene) in a "molecular tweezers"-like configuration were synthesized and evaluated for the separation of SWNTs. While the mono-derivative was incapable of the noncovalent functionalization–solubilization, the bis-anthracene was found to be very effective. The results suggest that molecular tweezers of a tethered pair of planar aromatic species can be coupled with the selection of a suitable solvent or solvent mixture for effective and efficient post-production separation of metallic and semiconducting SWNTs.