Aggregation-Free, Highly Soluble CN-Terminated Dicyclopentadiene-Fused Rylenes
Liuying Jiao, Ya Zou, Wei Fan, Yi Han, Qifeng Zhou, Jiawei Shao, Jishan Wu
Abstract
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.