Sulfur/selenium atom-incorporated hetero[7]helicenes for low-temperature circularly polarized phosphorescence

Abstract

Three new thiophene/selenophene-based S/Se-[7]helicenes were efficiently synthesized via intermolecular McMurry and oxidative photocyclization reactions. Their helical structures were confirmed through single-crystal analysis. Additionally, these [7]helicenes exhibited notable circularly polarized phosphorescence at 77 K. Theoretical calculations show that both intersystem crossing channels and spin–orbit coupling constants are increased due to the heavy atom effect.