Chiral Helical Metal–Organic Frameworks with Intrinsic Spin Polarization Enable Enantioselective Electropolymerization

The chirality-induced spin selectivity (CISS) effect provides a nonmagnetic route to generate spin-polarized charge transport, yet converting spin selectivity into intrinsic chemical asymmetry within crystalline materials remains a fundamental challenge. Here, we report an enantiomeric pair of chiral helical Fe- and Cr-based metal-organic frameworks (MOFs) assembled from homochiral bipyridine ligands and trinuclear metal clusters, which function as intrinsically spin-polarizing platforms for enantioselective electropolymerization. Single-crystal X-ray diffraction (SC-XRD) reveals long-range helical architectures featuring continuous one-dimensional transport channels. Magnetic conductive atomic force microscopy (mc-AFM) demonstrates pronounced CISS behavior, with spin polarization ratios reaching up to 90% for the Fe-MOFs and ∼74% for their Cr analogues, reflecting metal-dependent spin-orbit coupling (SOC) effects. When processed as thin films on nonmagnetic electrodes, the Fe-MOFs intrinsically generate spin-polarized currents without external magnetic fields and govern the stereochemical outcome of electropolymerization, enabling the enantioselective growth of polythiophene derivatives from achiral monomers. In contrast, the isostructural Cr-MOFs exhibit weaker spin polarization and induce reduced chiral responses during polymerization. Notably, this work represents the first demonstration of CISS-driven asymmetric electropolymerization originating from chiral materials and identifies chiral MOFs as a versatile platform for translating CISS into enantioselective chemical synthesis.