Alternately Twisted, Electron‐Rich Rylenes and Their Stable Cations

Abstract

ABSTRACT Solution‐phase synthesis of long rylenes remains challenging due to their strong tendency to aggregate. Introducing backbone twist can reduce aggregation and simultaneously generate potential helical chirality. Herein, we report a series of rylene molecules–up to octarylene—bearing both odd‐ and even‐numbered naphthalene units and multiple n ‐butoxy substituents at the bay/ortho positions, synthesized via stepwise cross‐coupling followed by controlled oxidative dehydrogenation. Peri ‐attached 4‐(trifluoromethyl)phenyl groups further stabilize the extended scaffolds. The electron‐rich n ‐butoxy groups not only induce pronounced backbone twisting but also impart strong electron‐donating character. X‐ray crystallography reveals that long rylenes with two or more bay‐ tetra( n ‐butoxy) motifs adopt alternating P / M helicity rather than a homochiral helical conformation. These molecules exhibit clear length‐dependent optical and electrochemical properties, with absorption and emission spanning the visible to near‐infrared region. Their electron‐rich nature enables facile formation of stable radical cations and dications. Solid‐state structures of representative radical cations show distinct intermolecular stabilizing interactions, while 1 H NMR and ACID analyses of the dications reveal a systematic evolution from local to global aromaticity.