Highly selective detection of Fe3+, Cd2+ and CH2Cl2 based on a fluorescent Zn-MOF with azine-decorated pores

The design and synthesis of sensitive and selective luminescent materials as chemical sensing agents is a fundamental goal in fluorescence assays. Considering high porosity, large surface area, excellent photo-luminescence property of metal-organic frameworks (MOFs), luminescent properties of a microporous azine-functionalized MOF, TMU-16, dispersed in different metal ions and solvents have been investigated systematically. 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 mu M, respectively. The effect of other metal ions on the fluorescence intensity of the MOF was also studied and other metal ions showed low interference response in recognition of Fe3+ and Cd2+. Furthermore, TMU-16 exhibits 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.