A colloidal water-stable MOF as a broad-range fluorescent pH sensor via post-synthetic modification

Abstract

We report for the first time the pH-dependent fluorescence of UiO-66-NH2 across the wide range from 1 to 9. By application of a post-synthetic modification (PSM) diazotisation strategy, we synthesized a new material, UiO-66-N=N-ind, which shows increased chemical stability and enhanced sensing up to pH 12.

Function-led design of new porous materials

“…The hydrolytic stability of MOFs has since been greatly improved using design strategies such as hydrophobic organic linkers (80) or postsynthetic modification with diazo groups (81). UiO-66 and its derivatives were shown to retain their structural stability after immersion in water and 0.1 M HCl solutions; HKUST-1 (Cu-BTC) is waterstable under certain conditions but degrades at higher relative humidities and/or temperatures [90% relative humidity (RH) at 298 K] (82).…”

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.…”

Stability of UiO-66 under acidic treatment: Opportunities and limitations for post-synthetic modifications

“…The self-assembly of MOFs with already functionalized linkers is not always an accessible pathway, since the presence of functional groups can easily affect the crystal growth process. On the other hand, post-synthetic modifications (PSM) of the linkers is appearing as a more promising approach as reported in copious recent examples [12][13][14][15]. However, the success of performing a PSM strongly depends on the chemical and thermal stability of the MOF, which represents, so far, the major limitation to introduce new functional groups.…”