Construction And Property Of Supramolecular Polymers Self-Assembled From Hydrazide-Based Cyclic Hexamers

Supramolecular polymer, as a cross discipline of supramolecular chemistry and polymer chemistry, is receiving more and more attention in recent years. The current thesis is based on a cyclic hexamer self assembled from a ditopic hydrazide monomer linked by a 120o isophthalamide spacer via hydrogen bonding interaction. We combined hydrogen bonding with host-guest complexation or π-π stacking interaction to construct supramolecular polymers, and the self-assembly behavior and the nature of the supramolecular polymers were studied.In the first part of this thesis, we obtained a supramolecular polymer by using orthogonal hydrogen bonding and host-guest complexation. Herein, dibenzo-24-crown-8 motif was introduced into 5-position of isophthalamide spacer of hydrazide based self-assembly monomer. By means of hydrogen bonding driving self assembly, six 24-crown-8 motifs were introduced into each vertex of the cyclic hexamer. This cyclic hexamer subsequently polymerized into a supramolecular polymer network upon addition of a ditopic dibenzylammonium salt due to the host-guest complexation between the crown ether and ammonium moieties. The supramolecular polymer formation was confirmed by NMR, scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Moreover, at high concentrations the resulting supramolecular polymer became a gel and showed multiple-stimuli-responsiveness. Thermo- and cation-induced gel-sol transitions were found to be completely reversible.In the second part of this thesis, we demonstrated that a perylene bisimide based supramolecular polymer system could be constructed through orthogonal hydrogen bonding and π-π stacking. Perylene bisimide was introduced into the vertexes of a hydrazide-based self-assembled cyclic hexamer. Subsequent stacking of the cyclic hexamers via π-π interaction of perylene bisimide moity led to formation of a supramolecular polymer with columnar structure. UV/Vis and fluorescence spectra confirmed the above conclusion.