Lanthanides based metal organic frameworks for luminescence sensing of toxic metal ions

Two set of lanthanides-based metal organic framework structures incorporating 2,6-naphthalenedicarboxylic acids and 1,5 dihydroxy-2,6-naphthalenedicarboxylic have been successfully synthesized and fully characterized. Interestingly, when 1,5 dihydroxy-2,6-naphthalenedicarboxylic was employed as organic linker, the hydroxyl groups were not involved in the coordination to the lanthanide clusters and therefore hydroxyl-functionalized lanthanides MOFs (AUBM-3) were obtained. The photophysical properties of both set of MOFs were studied and their sensing properties for toxic elements Pb(II), Cr(III), As(III), Cd(II), and Hg(II) and for paraquat were investigated. The hydroxyl-functionalized structures have shown to be promising luminescent sensory materials with high selectivity and sensitivity to mercury.