A Zn(II)-Based Metal–Organic Framework Constructed from Cyclotriphosphazene Hexacarboxylate and π-Conjugated Bisterpyridine Ligands for Dual Applications in Dye Photodegradation and VOC Sensing

Abstract

The increasing demand for sustainable materials capable of addressing both water and air pollution has stimulated the search for multifunctional MOFs with integrated properties. Herein, we report the solvothermal synthesis of a novel Zn(II) MOF PCP-35 constructed from a cyclotriphosphazene-based hexacarboxylic acid ligand (H6L) and a bisterpyridine (bisterp) N-donor. ingle-crystal X-ray diffraction analysis revealed a robust three-dimensional (3D) framework, in which Zn–O bonds from the phosphazene-derived hexacarboxylate units and Zn–N bonds from the bisterp. ligands generate interconnected porous channels, while pronounced π–π stacking interactions between the bisterp. ligands further stabilize the architecture, reflecting a rational ligand-design strategy. The material was thoroughly characterized by PXRD, FTIR, TGA, UV–vis DRS, SEM, and solid-state photoluminescence spectroscopy. The multifunctional nature of this Zn(II)-based framework is reflected in its dual performance: under visible-light irradiation, it efficiently catalyzes the degradation of methylene blue, methyl orange and rhodamine B, achieving over 90% degradation within one hour and maintaining stability across multiple cycles; in addition, its strong luminescence response allows for selective sensing of volatile organic compounds, particularly aldehydes, through distinct fluorescence quenching and enhancement behaviors. This dual-functionality, arising from the synergistic interplay of the robust phosphazene scaffold and conjugated bisterp. pillar, highlights the potential of Zn(II) MOFs as versatile platforms for environmental remediation and chemical sensing.