A Helical Tubular Dyad of [9]Cycloparaphenylene: Synthesis, Chiroptical Properties and Post-functionalization

Angew Chem Int Ed Engl. 2024 Nov 25:e202419435. doi: 10.1002/anie.202419435. Online ahead of print.

Abstract

The bottom-up synthesis of discrete tubular molecules that mimic the structural features of carbon nanotubes has been a long-standing pursuit for synthetic chemists. As the shortest segments of armchair-type carbon nanotubes, cycloparaphenylenes are regarded as ideal macrocyclic building blocks for achieving this goal. Here we report the synthesis of a helical tubular molecule featuring three diyne linkers between two site-specifically functionalized [9]cycloparaphenylene. Its C3-symmetrical, radially conjugated structure and solid-state packing have been elucidated by spectroscopic and crystallographic characterizations. Notably, the resolved enantiomers display a circularly polarized luminescence brightness value of 1.47 × 103 M-1 cm-1, which is among the highest values for chiral organic molecules. Furthermore, the diyne-linked molecule could be directly converted into a thiophene-linked helical molecule, demonstrating the post-functionalization approach for the construction of chiral tubular molecules from cycloparaphenylenes.

Keywords: circularly polarized luminescence; cycloparaphenylene; helical chirality; site-specific functionalization; tubular molecule.