Coordination-driven reorganization of supramolecular assemblies enables enhanced spin-selective charge transport

The chiral-induced spin selectivity (CISS) effect provides a powerful method for generating spin-polarized currents in organic, inorganic and hybrid molecular systems without the need for magnetic materials. Nevertheless, the understanding of how coordination-driven reorganizations-from supramolecular assemblies to coordination frameworks-influence the CISS effect within a single platform remains limited. Here, we report a phenylalanine-functionalized naphthalene diimide (FNDI) system that undergoes a controlled transformation from supramolecular assemblies to copper-coordinated assemblies. The supramolecular assemblies of FNDI exhibit pronounced spin-selective transport arising from their helical arrangement. Upon coordination with copper (Cu²⁺) ions, the system reorganizes into a more rigid architecture with enhanced spin-orbit coupling, leading to a significant amplification of spin polarization. Electrochemical measurements support coordination-induced modulation of ligand-centered redox behavior indicating strong metal-ligand interaction. Spin-dependent transport measurements using magnetic conductive atomic force microscopy (mc-AFM) demonstrate a significant improvement in spin-filtering efficiency in the coordinated system, while Kelvin probe force microscopy (KPFM) further highlights magnetization-dependent surface potential contrasts, accentuating the crucial role of contact potential difference in governing the CISS effect. Collectively, these findings establish coordination chemistry as a promising molecular design principle for engineering and tuning CISS-based spintronic materials, thereby paving the way for the advancement of high-performance molecular spintronic materials.