Double Thia/sulfone[7]helicenes with Controlled Photophysical and Chiroptical Properties by Heteroatom Variation.

The development of helicenes with strong chiroptical response and controlled photophysics is highly desirable but challenging. In this work, double thia/sulfone[7]helicenes were synthesized to investigate the heteroatom effect on the photophysical and chiroptical properties of double heterohelicenes through comparison with the previously reported double oxa[7]helicene. By variation of the embedded heteroatoms from oxygen to sulfur, the absorption and emission were significantly red-shifted, along with the improved luminescence dissymmetry factor (g lum ). In particular, the double sulfone[7]helicene exhibited strong red to near-infrared (NIR) emission with g lum of 1.1×10 -3 , suggesting its potential as a NIR circularly polarized luminescence emitter.