Perylene functionalized Fluorescent Zirconium based Metal Organic Frameworks for selective sensing of Cu2+, Pb2+, and Fe3+ ions

Abstract

A highly fluorescent amide-linked MOF (UiO-66-NH-PTCDA-Na) was produced by post-synthetically modifying UiO-66-NH2 with the π-conjugated organic linker PTCDA-Na. The structural, optical, thermal, morphological, and surface features were examined by various spectroscopic methods (PXRD, UV-DRS, FT-IR, TGA, XPS, FESEM, and BET). This luminescent MOF was a perfect choice for fluorescence sensing applications since it showed intense cyan emission (λmax = 479 & 514 nm) in an aqueous condition (HEPES buffer, pH = 7.0). The presence of carboxylate binding sites and an extended π-electron system which collectively contribute to enhanced emission properties and facilitated metal-ion interactions. This strong emission of UiO-66-NH-PTCDA-Na was quenched towards Cu2+, Pb2+, and Fe3+, with LOD values of 3.76, 3.14, and 4.31 μM, respectively. Fluorescence lifetime (TCSPC) studies confirmed that dynamic fluorescence quenching occurs due to MOF-analyte interactions. These results showed that this modified MOF (UiO-66-NH-PTCDA-Na) as a promising fluorescence quenching sensor for micromolar level metal ion detection (Cu2+, Pb2+, and Fe3+) in real water environmental systems.