Volume 28, Issue 21 e202104175
Research Article

Unfolding the Role of Building Units of MOFs with Mechanistic Insight Towards Selective Metal Ions Detection in Water**

Sahel Fajal

Sahel Fajal

Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008 India

These authors contributed equally to this work.

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Writakshi Mandal

Writakshi Mandal

Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008 India

These authors contributed equally to this work.

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Dipanjan Majumder

Dipanjan Majumder

Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008 India

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Mandar M. Shirolkar

Mandar M. Shirolkar

Symbiosis Center for Nanoscience and Nanotechnology (SCNN), Symbiosis International (Deemed University) (SIU), Lavale, Pune, 412115 India

Department of Physics, Tamkang University, Tamsui, 251 Taiwan

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Yogeshwar D. More

Yogeshwar D. More

Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008 India

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Prof. Dr. Sujit K. Ghosh

Corresponding Author

Prof. Dr. Sujit K. Ghosh

Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008 India

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First published: 22 February 2022
Citations: 4
**

MOF=metal-organic frameworks.

Graphical Abstract

Selective ferric ions detection has been carried out with systematic screening by varying number of Lewis basic (pyridyl-N atoms) sites in a series of isostructural, robust UiO-67 MOFs. Among them, al the three fluorescent MOFs are seen to present quenching response towards Fe3+ ions in water. However, UiO-67@N exhibits highly selective and sensitive response, whereas emission of both UiO-67 and UiO-67@NN is quenched by several metal ions.

Abstract

The potential emergence of fluorescence-based techniques has propelled research towards developing probes that can sense trace metal ions specifically. Although luminescent metal-organic frameworks (MOFs) are well suited for this application, the role of building blocks towards detection is not fully understood. In this work, a systematic screening by varying number of Lewis basic (pyridyl-N atoms) sites is carried out in a series of isostructural, robust UiO-67 MOFs, and targeting a model metal ion-Fe3+. All the three fluorescent MOFs are seen to present quenching response towards Fe3+ ions in water. However, UiO-67@N exhibits highly selective and sensitive response, whereas emission of both UiO-67 and UiO-67@NN is quenched by several metal ions. Detailed experimental and theoretical mechanistic investigation is carried out in addition to demonstration of UiO-67@N being able to sense trace amount of Fe3+ ions in synthetic biological water sample. Further, UiO-67@N based mixed-matrix membrane (MMM) has been prepared and employed to mimic the real time Fe3+ ions detection in water.

Conflict of interest

The authors declare no conflict of interest. All authors have given approval to the final version of the manuscript.

Data Availability Statement

Research data are not shared.