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

Abstract Two new pentagon‐embedded carbo11helicenes have been designed and synthesized in a three‐step process, which are the first example of carbo11helicenes 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 AgSbF 6 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.