Fluorescent zinc(ii)-based metal–organic frameworks for nitroaromatics sensing

Abstract

A new structural metal–organic framework with fluorescence properties, namely Zn₄(BTC)₂(OH)₂(CH₃OH)₆ (NJMU-001), was synthesized by using 1,3,5-benzenetricarboxylic acid (H₃BTC) and zinc nitrate through a solvothermal reaction. In order to obtain good single crystals of NJMU-001, the factors affecting the reaction, such as the reaction temperature, reaction time, solvent and metal salt/ligand molar ratios, were studied. The phase purity of NJMU-001 was investigated via powder X-ray diffraction analysis, elemental analysis and FT-IR spectroscopy. Gas sorption measurements revealed that NJMU-001 was microporous and thermogravimetric analysis indicated that it was thermally stable under 200 °C. Fluorescence study of NJMU-001 in an N,N-dimethylformamide medium showed blue emission at 435 nm upon excitation at 370 nm. This emissive property was used for sensitive sensing of toxic and explosive nitroaromatics by exhibiting fluorescence quenching.