Abstract
As one of common dynamic covalent bonds, acylhydrazone bond plays an important role in developing intelligent responsive materials. In this report, we present acylhydrazone-based dynamic polymers with multi-stimuli responsiveness, particularly metal recognition behaviours and their modulation. A series of polyacylhydrazones with different metal-binding sites were designed and prepared in a modular fashion. Titration of these receptors with a diverse set of metal ions, including Cu(2+), Zn(2+) and La(3+), resulted in unique optical changes, and both the sensitivity and selectivity profiles can be regulated. Moreover, the metal-binding feature was facilely modulated by changing the solvent. The addition of weakly basic anions was employed to further fine-tune the responsiveness of the polymers by taking advantage of the cooperative effect with metal coordination. Finally, the sensitive detection of 6-mercaptopurine and pyrophosphate was achieved to demonstrate the application potential of these systems.