Issue 3, 2021

A selective detection of nanomolar-range noxious anions in water by a luminescent metal–organic framework

Abstract

A new metal–organic framework (MOF) showed excellent recognition ability toward five toxic oxo-anions, namely arsenate (HAsO42−), phosphate (PO43−), permanganate (MnO4), chromate (CrO42−), and dichromate (Cr2O72−) in aqueous medium upon irradiation with UV light. The MOF [Y(tp)(ox)0.5(H2O)2]·H2O, 1 and a 20% Tb-doped MOF [Y0.8Tb0.2(tp)(ox)0.5(H2O)2]·H2O, 1a were synthesized by the self-assembly of Y(III)/Tb(III), terephthalic acid (H2tp), and oxalic acid (H2ox) under hydrothermal conditions. The crystal structure of 1 demonstrated three-dimensional structures with water occupying a one-dimensional channel. Upon UV light exposure, an aqueous suspension of 1a exhibited strong green luminescence. This luminescence showed a colour change when water was contaminated by the said anions. Several other interfering anions were also tested to establish its selectivity as a chemosensor toward the aforementioned anions. The estimated limit of detection (LOD) of 1a for these anions was 41.7, 33.5, 19.6, 40.8, and 43.9 nM for HAsO42−, PO43−, MnO4, CrO42−, and Cr2O72−, respectively, which were significantly lower than the levels recommended for these anions in the aqueous environment. The root of the luminescence quenching of 1a in the presence of such a low concentration of aforementioned anions was due to the interruption of the sensitization process of the Tb centre. Anions HAsO42−, PO43−, and MnO4 entered the channel of MOF and interacted with Y3+/Tb3+ centres at the molecular-level, which hampered the energy flow from the ligand to the metal centre through a weakening of Tb–O bonds of carboxylates, resulting in a quenching of the Tb centre emission with a concomitant enhancement of the ligand centre emission. Additionally, in the case of the MnO4 ion, an inner filter effect also contributed to the quenching of the Tb centre emission, but to a smaller extent. For CrO42− and Cr2O72− anions, the inner filter effect is the key mechanism for the luminescence intensity reduction. Besides, these analytes could also reduce the energy flow from the ligand to the lanthanide ion, which led to the luminescence quenching.

Graphical abstract: A selective detection of nanomolar-range noxious anions in water by a luminescent metal–organic framework

Supplementary files

Article information

Article type
Paper
Submitted
19 oct. 2020
Accepted
17 dic. 2020
First published
17 dic. 2020
This article is Open Access
Creative Commons BY-NC license

Mater. Adv., 2021,2, 985-995

A selective detection of nanomolar-range noxious anions in water by a luminescent metal–organic framework

P. Daga, S. Sarkar, P. Majee, D. K. Singha, S. Hui, P. Mahata and S. K. Mondal, Mater. Adv., 2021, 2, 985 DOI: 10.1039/D0MA00811G

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements