Methanol Sensing by a Luminescent Zinc(II)-Based Metal-Organic Framework

Abstract

A luminescent zinc-based metal-organic framework (MOF; 1) was synthesized from a highly conjugated tridentate ligand, 1,3,5-tris[(1E)-2'-(4''-benzoic acid)vinyl]benzene. X-ray single crystal analysis reveals the organization of 1 in a three-dimensional porous framework. Thermogravimetric analysis shows that 1 has a good thermal stability, and resists decomposition up to 420 °C. The removal of the solvent molecules from the cavities leads to a temporary loss of crystallinity, which can be regained by heating the MOF in diethylformamide, the solvent used for the synthesis, as shown by powder X-ray diffraction. In addition, 1 shows luminescent features influenced by the chemical environment, making it suitable as optical sensor. Detection of methanol with a turn-on effect was possible in low concentration in mixtures with water (50 μL/3 mL and 10 μL/3 mL) and as vapor.

Keywords: luminescence; metal-organic frameworks; methanol; sensors; zinc.