Preparation Of Helical Polymers With Controllable Handedness By Metal Ion-Mediated Supramolecular Template Method

Precise adjustment of the microstructure and optical activity of chiral nanomaterials is essential to control their properties.Supramolecular nanostructures with controllable chirality have attracted much attention because of their excellent performance in asymmetric catalysis,enantiomeric separation and chiral switching.In recent years,numerous single chiral nanomaterials have been prepared through typical supramolecular template methods.However,in enantiomerically pure template systems,it is still challenging to dynamically regulate the optical activity and microstructure of the transcription products（especially carbon-based materials）.Therefore,this article aims to prepare highly cross-linked carbon-based polymer nanomaterials with controllable optical activity and microstructure through the metal ion-mediated supramolecular template method,which might provide a good foundation for being widely used in chiral sensing,microwave absorption,circularly polarized luminescence,and chiral separation.This dissertation first utilized the assemblies of phenylglycine derivative(L-Phg C₁₆)as templates in an enantiomerically pure template system,and after adding 3-aminophenol（3-AP）and formaldehyde,the left-handed helical 3-aminophenol formaldehyde resin nanotubes（LAPF）could be obtained after phenolic polymerization and removal of the templates.When different metal ions were further introduced to co-assemble with L-Phg C₁₆,APF with different nanostructures could be collected.Especially when Mn²⁺/Co²⁺/Ni²⁺with moderate coordination ability was added,the macroscopic helical structure and optical activity of the obtained phenolic resins were opposite to those obtained from the metal ion-free system.By carbonizing the corresponding APF,carbonaceous nanotubes with the non-collapsed helical structure could also be collected.At the same time,this dissertation focused on the mechanism of the chirality inversion of the obtained phenolic resins mentioned above.Through scanning electron microscopy,transmission electron microscopy,diffuse reflection circular dichroism,infrared spectroscopy,X-ray diffraction and Zeta potential,a series of studies had shown that the spatial arrangement transformation（from Hydrogen bonds dominating to Coordination bonds dominating）of template molecules induced by the metal coordination resulted in the chirality inversion of phenolic resin nanotubes.Different metal ions possessed different coordination abilities,which led to different stacking methods of supramolecular assemblies(L-Phg C₁₆-Metal complexes),and then transcribed different nanostructured phenolic resins.In addition,the metal ion-mediated supramolecular template method greatly increased the interaction between the active monomer and the supramolecular assemblies compared with the traditional non-metal ion system,thereby expanding the range of experimental conditions for preparing chiral nanomaterials.This new synthesis concept can be applied to the preparation of multifunctional chiral nanomaterials.Further changing the amine active monomers,the metal ion-mediated supramolecular template method could also be applied to fabricate chiral poly（m-phenylenediamine）and corresponding carbonaceous nanotubes with controllable microstructure in an enantiomerically pure template system.The active amino group contained in the molecular structure of poly（m-phenylenediamine）makes it possess excellent application potential in the fields of chiral separation and energy storage.