Stable Zr(IV)-Based Metal–Organic Frameworks with Predesigned Functionalized Ligands for Highly Selective Detection of Fe(III) Ions in Water

Abstract

Metal-organic frameworks are a class of attractive materials for fluorescent sensing. Improvement of hydrolytic stability, sensitivity, and selectivity of function is the key to advance application of fluorescent MOFs in aqueous media. In this work, two stable MOFs, [ZrO(OH)(HO)(L)] (BUT-14) and [ZrO(OH)(HO)(L)] (BUT-15), were designed and synthesized for the detection of metal ions in water. Two new ligands utilized for construction of the MOFs, namely, 5',5‴-bis(4-carboxyphenyl)-[1,1':3',1″:4″,1‴:3‴,1''''-quinquephenyl]-4,4''''-dicarboxylate (L) and 4,4',4″,4‴-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl))tetrabenzoate (L), are structurally similar with the only difference being that the latter is functionalized by pyridine N atoms. The two MOFs are isostructural with a sqc-a topological framework structure, and highly porous with the Brunauer-Emmett-Teller (BET) surface areas of 3595 and 3590 m g, respectively. Interestingly, they show intense fluorescence in water, which can be solely quenched by trace amounts of Fe ions. The detection limits toward the Fe ions were calculated to be 212 and 16 ppb, respectively. The efficient fluorescent quenching effect is attributed to the photoinduced electron transfer between Fe ions and the ligands in these MOFs. Moreover, the introduced pyridine N donors in the ligand of BUT-15 additionally donate their lone-pair electrons to the Fe ions, leading to significantly enhanced detection ability. It is also demonstrated that BUT-15 exhibits an uncompromised performance for the detection of Fe ions in a simulated biological system.

Nanoscale Metal–Organic Frameworks for Therapeutic, Imaging, and Sensing Applications

“…nMOF‐based systems to detect metal ions such Cu 2+ and Fe 3+ have been developed based on luminescence quenching of the Tb 3+ or Eu 3+ ions . Water stable MIL‐53(Al) and Zr(IV) based BUT MOFs (where BUT refers to Beijing University of Technology) have also been reported as Fe 3+ sensors, based on SBU ion exchange and Lewis base‐induced ion inclusion in the channels, respectively …”

The Impact of Synthesis Method on the Properties and CO2 Sorption Capacity of UiO-66(Ce)

“…It is characterized by good thermal and chemical stability, thanks to strong Zr-O bonds. Moreover, the UiO-66 structure exhibits excellent stability in water [7] and promising features for CO 2 /CH 4 gas separation [8]. By changing metal in the node or preparation allows accelerated nucleation; hence, at low reaction temperature and ambient pressure, crystallization time is short.…”

Ferrocene particles incorporated into Zr-based metal–organic frameworks for selective phenol hydroxylation to dihydroxybenzenes

“…15 The strong Zr-O bonds make UiO-66 exhibit higher thermostability and chemical stability. Furthermore, UiO-66 also demonstrated the excellent stability of structure when soaked in water, 16 which could still be retained aer introduced with missing-linker defects and modied by active functional groups. 17,18 Owing to the peculiarity of prominent structural stability, the development of UiO-66 based catalysts has attracted more and more research interests.…”