Luminescent Metal–Organic Framework TMU-16as a Sensor for Metal Ions and Small Molecules

Nowadays, Metal-organic frameworks (MOF) with functional pore structures as a new type of sensing materials have attracted the increasing attention in fluorescence assays [1]. In this research, we explored an interpenetrating microporous mixed-ligand MOF for highly selective and sensitive detection of metal ions. A Zn(II)-based metal-organic framework, [Zn2(H2-BDC)2(4-bpdh)]·3DMF (TMU-16), have been successfully synthesized via a mixed ligand approach using 1,4-benzenedicarboxylate (H2-BDC) and 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh) under solvothermal conditions [2].The TMU-16 displays superb luminescence emission, and it can detect Fe(III) and Cd(II) ions with high selectivity, excellent sensitivity, and short response time (<1 min). The emission intensities of TMU-16 were quenched upon the addition of Fe3+ and increased upon the addition of Cd2+. The detection limits of TMU-16 for Fe3+/Cd2+ in DMF are estimated to be 0.2 and 0.5 μM, respectively. Furthermore, TMU-16exhibits distinct solvent-dependent luminescent spectra with emission intensity significantly enhanced toward dichloromethane. More importantly, this is the first example of MOF-based luminescent sensor as efficient multifunctional fluorescence material which can use for selective sensing of Fe(III) and Cd(II) ions and small molecules such as CH2Cl2 (Fig. 1).