No abstract

A carbonaceous bearing of a minimal form has been assembled using a finite carbon nanotube molecule and a functionalised fullerene molecule. With the van der Waals attraction, the bearing holds the fullerene journal tightly to prevent its run-out motion, and the journal with a shaft rolls anisotropically in the bearing despite the tight holding constraint. Ensemble motion has been revealed spectroscopically at the molar quantity level.

The last remaining synthetic target of finite single-wall carbon nanotube models, the zigzag nanotube, has been accomplished through bottom-up chemical synthesis. The zigzag nanotube was synthetically accessible without constructing long-sought yet elusive cyclacene structures but with a cycloarylene structure by devising its cutout positions. The persistent tubular shape was also perfected in this last model by cyclization of zigzag-shaped aromatic molecules with a synchronous topological arrangement. The crystal structure of this nanotube further revealed an entangled supramolecular assembly, which showed a novel way to align nanotube molecules by utilizing their open-end functional groups in a thread-in-bead molecular assembly.

Belt-persistent tubular cycloarylenes possessing extended sp 2 -networks of finite single-wall carbon nanotubes (SWNT) have been synthesised from an abundantly available pigment possessing the dibenzo[def,mno]chrysene (anthanthrene) framework. The introduction of bulky substituents allowed for the diastereoselective production of a single helical isomer as a racemate, and the extension of the p-systems in the cycloarylene unexpectedly lowered the enthalpic barrier for the rotation of the arylene unit. Crystallographic analysis of the helical finite SWNT molecules revealed alternate layers of homohelical columns.