Unprecedented Solvent-Dependent Sensitivities in Highly Efficient Detection of Metal Ions and Nitroaromatic Compounds by a Fluorescent Barium Metal–Organic Framework

The assembly of a fluorescent dicarboxylate ligand with a barium ion resulted in the formation of a 3D metal–organic framework, Ba5(ADDA)5(EtOH)2(H2O)3·5DMF (UPC-17), based on a 1D rod-shaped secondary building unit. The unprecedented solvent-dependent sensitivities of UPC-17 for the detection of Fe3+/Al3+ ions and 4-nitrophenol with high efficiency were observed for the first time. Significantly, UPC-17 exhibits superior “turn-off” detection for the Fe3+ ion in methanol and acetone emulsions but shows “turn-on” detection in tetrahydrofuran emulsion. Furthermore, the visible color changes in the detection process make them easy to distinguish by the naked eye, which further increases its application potential.