Straightforward Synthesis of Pentagon‐Embedded Expanded [11]Helicenes for Radiative Cooling Property

Abstract

AbstractTwo new pentagon‐embedded carbo[11]helicenes have been designed and synthesized in a three‐step process, which are the first example of carbo[11]helicenes through the post‐functionalization of twistacene. TD‐DFT analyses indicate that both of them possess high enantiomerization barriers of 42.29 kcal/mol and 40.76 kcal/mol, respectively. They emit strong red fluorescence and can be chemically oxidized into stable cationic radicals upon addition of AgSbF6 evidenced by the bathochromic‐shifted absorption spectra and the appearance of electronic paramagnetic resonance (EPR) signals. In addition, such helical derivatives can be chosen as radiative cooling materials in a glass model house, and the maxima of 5.4 °C for the former and 6.5 °C for the latter are found in the comparative tests, which might be caused by the NIR reflective response.