Differential Metal Ion-Sensing Properties of Isomeric Crystalline Polyacylhydrazone Organogelators

Abstract

Two isomeric polyacylhydrazones P-1 and P-2 were prepared by dynamic covalent chemistry. Due to the presence of aromatic moieties and intramolecular hydrogen bonds in the backbone, both polymers exhibited very high crystallinity. Furthermore, they had shown to be very strong physical gelators for aromatic solvents. Upon interacting with metal ions, the two polymers demonstrated different yet specific metal ion-responsive properties such as gel-to-sol transition, gel strength reinforcement, and/or quenching/enhancement of fluorescence intensity. Based on solid-state NMR and powder X-ray diffraction data, the metal ion binding mechanisms were elucidated and a model was proposed to rationalize the differences in their metal ion-responsive properties. This work showed that these crystalline polyacylhydrazone polymers possess very rich supramolecular and stimuliresponsive properties and can be used for metal ion-sensing applications via visual sol−gel transitions.

Preparation and Specific Detection of Zn2+ Ions of Polyacylhydrazones with Polymerization‐Induced Emission

“…This result was consistent with the descriptions described in the literature. [ 38 ] Additionally, the comparison of three configurations of aromatic polyacylhydrazone showed that there was little difference in their fluorescence, and the fluorescence intensity of polyacylhydrazone from p ‐phthalaldehyde was slightly higher, possibly due to its symmetrical structure. In brief, the aliphatic polyacylhydrazone provided more characterization and performance regulation as subsequently described.…”

Polymeric Emissive Materials Based on Dynamic Covalent Bonds

“…For example, Fang et al fabricated a tetraphenylethylene-based acylhydrazone gel for luminescence sensing of Cu 2+ and subsequent CN − detection [ 47 ]. Similarly, Wang et al reported two crystalline polyacylhydrazone organogels whose fluorescence could respond to metal ions [ 48 ]. Very recently, the Tang group reported a phototriggered AIE (PTAIE) acylhydrazone gel which could be used for 4D soft patterns [ 49 ].…”

Supramolecular assembly of isomeric SN-38 prodrugs regulated by conjugation sites

“…1–3 One unique feature is that the physiochemical properties of supramolecular nanostructures can be facilely controlled via the molecular-level design of self-assembling building blocks. For example, the morphologies of peptide assemblies are highly sequence-specific 4–6 and sensitive to the amino acid position in isomeric peptide sequences. 7–9 In other examples, the self-assembly behavior of monomeric building blocks is controlled by the attachment and removal of enzyme cleavable pendant functional groups, enabling the sol–gel transition of supramolecular materials.…”