Highly sensitive and selective fluoride detection in water through fluorophore release from a metal-organic framework

Abstract

The detection, differentiation and visualization of compounds such as gases, liquids or ions are key challenges for the design of selective optical chemosensors. Optical chemical sensors employ a transduction mechanism that converts a specific analyte recognition event into an optical signal. Here we report a novel concept for fluoride ion sensing where a porous crystalline framework serves as a host for a fluorescent reporter molecule. The detection is based on the decomposition of the host scaffold which induces the release of the fluorescent dye molecule. Specifically, the hybrid composite of the metal-organic framework NH2-MIL-101(Al) and fluorescein acting as reporter shows an exceptional turn-on fluorescence in aqueous fluoride-containing solutions. Using this novel strategy, the optical detection of fluoride is extremely sensitive and highly selective in the presence of many other anions.

Switch‐On Fluorescence of a Perylene‐Dye‐Functionalized Metal–Organic Framework through Postsynthetic Modification

“…Synthesis of MIL‐101(Al)‐NH 2 : MIL‐101(Al)‐NH 2 was synthesized following a slightly modified procedure of Kapteijn and co‐workers 22. The reaction was carried out in a 50 mL glass reactor.…”

“…Moreover, an important challenge after incorporation of a fluorescence dye molecule inside the MOF structure is the possibility of luminescence quenching 14. 22 Quenching of an incorporated dye into the porous MOF scaffold could be caused by interaction of the dye with the metal centers, with the aromatic groups, or with functional groups of the organic linker. In addition, concentration‐ or self‐quenching‐effects of the dye itself could also be an issue.…”

Exploitation of Guest Accessible Aliphatic Amine Functionality of a Metal–Organic Framework for Selective Detection of 2,4,6-Trinitrophenol (TNP) in Water

“…These features result in the rational design and study of MOF materials for the desired selective detection of cations, anions, small molecules, explosives and biomolecules. 13,48,80,[86][87][88][89][90][91][92][93][94][95][96][97][98][99] In view of the targeted selective TNP detection in water by MOFs with high sensitivity, regardless of the latest advances, the reports of fluorescent MOFs exhibiting selective and sensitive TNP detection in concurrent presence of other nitro analytes are only few, while most of the reported MOFs involve detection only in organic/ organic-water mixture phase. 86 Subsequent to the discovery of the key role of lewis basic pyridyl functionality behind selective aqueous-media TNP sensing; 88 as a first-of-its kind approach, very recently, our group had come up with two reports of aqueous phase selective TNP-sensing based on two different MOF compounds.…”

A recyclable, fluorescent, and colorimetric sensor for fluoride anion in water using a crosslinked polymer functionalized with hydroxyl quinolinium

“…F − is also used in hypnotics, anesthetics, psychiatric drugs, and cockroach poisons. Numerous monomeric-based colorimetric and/or fluorescent chemosensors for F − have focused on systems containing imidazole, 7−10 urea, 11,12 thiourea, 13 naphthalimide, 14−17 coumarin, 18 spiropyran, 19 triarylborane, 20 phenanthroline, 21 quinoline, 22,23 arylaldoxime, 24 Rhodamine-Furan, 25 Si-O, 26 indole, 27 metal-organic frameworks, 28 diketopyrrolopyrrole, 29 or calix [4]pyrrole 30,31 moieties. Therefore, determination of F − is significant.…”