Structure-Driven Chirality-Induced Spin Selectivity in Self-Sorted Azahelicenes via Facile Electrosynthesis

Chiral-induced spin selectivity (CISS) has emerged as a powerful concept for directing spin-dependent transport in chiral materials design. Although helicenes are attractive chiral scaffolds for spin-selective functions, achieving high spin polarization remains challenging due to the difficulty in constructing highly ordered solid-state architectures. Here we report an electrochemical C‒H/N‒H coupling that enables rapid construction of a library of luminescent aza[5–9]helicenes. Single-crystal X-ray diffraction (SC-XRD) reveals rare β-type columnar packing and narcissistic chiral self-sorting into homochiral columns in both racemic and enantiopure crystals of bromo- and trifluoromethyl-substituted azahelicenes, driven by intermolecular π–π interactions together with intercolumnar C‒Br···N halogen bonding and C‒H···F contacts. As a result, thin films of these aza[7]helicenes exhibit pronounced chirality-dependent spin-selective charge transport with spin polarization ratios of up to 94% measured by magnetic conductive-probe atomic force microscopy (mc-AFM), along with circularly polarized luminescence (CPL) with dissymmetry factors of up to 1.4×10 ^− 2 . This work establishes a structure-driven strategy for enhancing chirality-induced spin selectivity, providing new insights into the design of chiral materials for spin-selective transport.