Circularly Polarized Luminescence in a Mobius Helicene Carbon Nanohoop

We present the first helicene carbon nanoohop that integrates a [6]helicene into [7]cycloparaphenylene. The [6]helicene endows the helicene carbon nanohoop with chiroptical properties and configurational stability typical for higher helicenes, while the radially conjugated seven para-phenylenes largely determine the optoelectronic properties. The structure of the helicene carbon nanoohop was unambiguously characterized by NMR, MS and X-ray analysis that revealed that it possesses a topology of a Mobius strip in the solid state and in solution. The chirality transfers from the [6]helicene to the para-phenylenes and leads to a pronounced circular dichroism and bright circularly polarized luminescence, which is affected by the structural topology of the nanohoop.

Automated summary

We have successfully synthesized a helicene carbon nanohoop with a unique structure and characterized its properties using NMR, MS, and X-ray analysis. The helicene carbon nanohoop exhibits chiroptical properties and configurational stability typical for higher helicenes, and also shows pronounced circular dichroism and circularly polarized luminescence.