A Novel Luminescent Metal–Organic Framework Based on Y(III) for Selective and Sensitive Detection of Trace Amounts of NACs and Fe 3+

A novel luminescent metal–organic framework (LMOF), [Y(H4L)(H2O)3]·2.5H2O (1), (H4L = 5-[1E)-(3-carboxy-4-hydroxyphenyl)diazenyl]benzene-1,3-dicarboxylic acid) was successfully constructed under hydrothermal conditions, which has a three-dimensional network structure with one-dimensional pores along the a-axis. 1 exhibits exceptional thermal stability and chemical stability and can serve as an excellent fluorescent probe for detecting trace amounts of nitroaromatic compounds (NACs) and Fe3+ in the environment, with high sensitivity and selectivity. Notably, the detection of Fe3+ remains unaffected by other competing metal ions. In addition, we prepared fluorescent test plates. Naked-eye detection and the preparation of luminescent test plates further increased its application potential. Finally, the fluorescence quenching mechanisms of NACs and Fe3+ on 1 were systematically investigated through experimental studies and theoretical calculations. The results demonstrated that, except for 4-Np, which exhibited solely static quenching, all other quenchers displayed the coexistence of both dynamic and static quenching mechanisms.