Aggregation-Free, Highly Soluble CN-Terminated Dicyclopentadiene-Fused Rylenes

Rylenes, known for their excellent photochemical properties, hold great promise in OLEDs, solar cells, and bioimaging applications. However, the solution-phase synthesis of long rylene molecules is often hindered by poor solubility and low stability. In this work, we present an efficient synthetic strategy for a series of CN-terminated rylenes via base-mediated intramolecular Michael addition and oxidative cyclodehydrogenation (Scholl reaction). The synthesized rylenes feature a cyclopentadiene ring at both bay positions of each perylene subunit and electron-deficient CN groups at the peri-termini. These structural modifications render the rylenes stable, aggregation-free, and highly soluble. Bulky aryl groups attached to the cyclopentadiene rings not only improve solubility but also block intermolecular π-aggregation, as revealed by XRD analysis. Additionally, the electron-withdrawing CN groups stabilize the π-conjugated system. The extended π-conjugation reduces the HOMO-LUMO gap, enhancing absorption and inducing a significant bathochromic shift into the NIR I and II regions.