Thioacetohydrazide-Cored Dendritic Metallogels with Multi-Stimuli-Responsive and Adsorptive Properties

A novel poly(aryl ether) dendritic ligand featuring a thioacetohydrazide functional group at the focal point was successfully designed and synthesized, along with its corresponding Zn(II) complexes formed through metal-ligand coordination. Notably, the dendritic Zn(II) complex demonstrated significantly enhanced gelation capabilities compared to their ligand precursors, achieving gel formation in various organic solvents at remarkably low critical gelation concentrations. Mechanistic investigations revealed that the formation of stable metallogels is facilitated by a synergistic combination of multiple noncovalent interactions, including Zn(II)-hydrazide coordination, solvophobic effects, and π─π stacking interactions. These dendritic metallogels exhibited intelligent stimuli-responsive behavior, undergoing reversible gel-sol phase transitions in response to various external stimuli, such as temperature and chemical inputs. Furthermore, the dendritic metallogel, particularly in its xerogel form, demonstrated exceptional efficacy (>94% within 10 hours) and outstanding adsorption capacity (800 mg/g) in the removal of Hg²⁺ ions from aqueous solutions, highlighting its potential for environmental remediation applications.