A water-stable lanthanide coordination polymer as a multiresponsive luminescent sensor for Fe

Area of Science:

• Materials Science
• Inorganic Chemistry
• Analytical Chemistry

Background:

• Lanthanide coordination polymers (Ln-CPs) are crucial for biological and environmental applications.
• Developing water-stable Ln-CPs is essential for systematic structure-property relationship studies.

Purpose of the Study:

• To synthesize and characterize a water-stable two-dimensional (2D) europium coordination polymer (Eu-CP).
• To investigate the luminescent properties of the Eu-CP.
• To evaluate the Eu-CP as a multiresponsive luminescent sensor for detecting specific analytes in aqueous solutions.

Main Methods:

• Synthesis of the Eu-CP using Eu(NO3)3·6H2O and a specific isophthalic acid derivative.
• Single crystal X-ray diffraction for structural analysis.
• Solid-state and solvent luminescence spectroscopy.
• Powder X-ray diffraction (PXRD) for water stability assessment.
• Sensing experiments in aqueous solutions.

Main Results:

• A 2D Eu-CP, {[Eu(L)(HCOO)]·H2O}n, was successfully synthesized with a structure featuring binuclear metal clusters.
• The Eu-CP exhibits bright, stable red luminescence due to the ligand-to-metal antenna effect.
• The luminescence is selectively quenched by Fe3+, Cr(VI) ions (CrO42-, Cr2O72-), and 4-nitrophenol (4-NP).
• Excellent water stability was confirmed through luminescence and PXRD studies in aqueous media.

Conclusions:

• The synthesized Eu-CP is a highly water-stable material with significant potential as a multiresponsive luminescent sensor.
• It enables sensitive and selective detection of Fe3+, Cr(VI), and 4-NP in aqueous solutions.
• The sensing mechanism is attributed to energy competition between analyte absorption and Eu-CP excitation.