Homochiral Single Crystals of Helical Polymer Nanotubes: Synthesis and Application.

The construction of helical polymer nanotubes with precise structure and enhanced stability remains a formidable challenge in synthetic chemistry, as it requires a complex balance of covalent and noncovalent interactions for hierarchical assembly. Herein, we report a hierarchical self-assembly strategy for the single-crystal synthesis of homochiral helical polymer nanotubes from simple, commercially available achiral monomers via synergistic dynamic covalent chemistry and noncovalent interactions. This one-pot process integrates the in situ formation of boroxine-based dynamic covalent bonds (B-O and B-N) to establish the polymer backbone, longitudinal hydrogen bonding (C≡N···H-N) to induce helical coiling, and π-π stacking to stabilize the enclosed nanotubular architecture. Through single-crystal X-ray diffraction and circular dichroism (CD) spectroscopy, we elucidate a crystallization-induced helical (CIH) nanotubulization mechanism, wherein linear polymer chains undergo supramolecular reorganization into homochiral helices during crystallization. The resulting nanotubes exhibit intrinsic chirality, hydrophilicity, aqueous stability, and strong photoluminescence properties. This work establishes a scalable, modular platform for synthesizing crystalline helical nanomaterials, bridging the gap between covalent polymer synthesis and nanotube design engineering for advanced optoelectronic and enantioselective applications.