5,12-Dichlorotetracene: A Building Block for an Axially Chiral Luminophore

Tetracene is an important building block for organic electronic materials. However, its halogenation has been a long-standing issue since it always affords a mixture of regioisomers, causing an inevitable cost as well as decreasing the reputation in materials development. Herein, we report a concise and regioselective synthesis of 5,12-dichlorotetracene through two steps in a total yield of 86%. Using the novel building block, we further synthesized an axially chiral tetracene together with its meso-isomer by installing two phenanthyl groups via Suzuki-Miyaura coupling. The chiral tetracene exhibited the Cotton effects in UV to visible region (300-530 nm). More importantly, it was found that the chiral tetracene works as a green circularly polarized luminophore with a luminescent dissymmetry factor of |g_CPL| = 3.1 × 10^-4 at 522 nm.