Construction of a Triazine-Based Fluorescent MOF for Aqueous Cr₂O₇^2– Detection and Gas Adsorption

Previously, we reported a 1,3,5-triazine-based metal-organic framework (MOF) constructed via the <i>in situ</i> hydrolysis of melamine. However, the use of template molecules within the pores posed significant challenges for material activation and resulted in pronounced fluorescence quenching. In this work, we introduce a more sustainable and template-free synthetic strategy by directly employing ammeline as the organic ligand to construct a triazine-based MOF, <b>SXU-120(ammeline)</b>. This approach simplifies the activation process, enhances solid-state fluorescence, and improves stability. The resulting MOF demonstrates high sensitivity and selectivity for aqueous Cr₂O₇^2- ions, achieving a Stern-Volmer quenching constant (<i>K</i>_SV) of 5.13 × 10⁴ M^-1. Furthermore, a scalable reflux-based synthesis route was developed, reinforcing the material's potential for practical and eco-friendly environmental sensing applications.