Unfolding the Role of Building Units of MOFs with Mechanistic Insight Towards Selective Metal Ions Detection in Water**
Sahel Fajal, Writakshi Mandal, Dipanjan Majumder, Mandar M. Shirolkar, Yogeshwar D. More, Sujit K. Ghosh
Abstract
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‐Fe 3+ . All the three fluorescent MOFs are seen to present quenching response towards Fe 3+ 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 Fe 3+ 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 Fe 3+ ions detection in water.