Metal-organic frameworks constructed with base-acid mixed ligands and its potential as dual-functional fluorescent probe toward Fe3+/Al3+ ions

Abstract

By virtue of mixed ligand strategy (2,5-Bis(1H-pyrazole-4-ylmethylene)-cyclopentanone and 2,5-dihydroxyterephthalic acid / terephthalic acid), four new metal–organic frameworks (MOFs) were fabricated and characterized. When 2,5-dihydroxyterephthalic acid acted as auxiliary ligand, MOFs 1–3 show 1D chain structure. 4 containing auxiliary ligand terephthalic acid (without − OH group) displays a 2D layer structure. Notably, 1 exhibits the significant selectivity toward Fe3+ and Al3+ ions, whereas the fluorescence intensity of 4 changed slightly in the presence of various metal ions, indicating that uncoordinated –OH in 1 plays an important role in sensing process. Moreover, it is revealed that 1 could act as dual-functional fluorescent probe toward Fe3+ and Al3+ with selectivity, sensitivity and reusability, and it could be prepared as fluorescent test papers for rapid on-site detection.