Anthracene-Based Lanthanide Coordination Polymer: Structure, Luminescence, and Detections of UO₂²⁺, PO₄^3–, and 2-Thiazolidinethione-4-carboxylic Acid in Water

Abstract

By the solvothermal assembly of Gd³⁺ and 5,5'-(anthracene-9,10-diyl)diisophthalic acid (H₄adip), an anthracene-based lanthanide coordination polymer (CP), [Gd₂(adip)(H₂adip)(NMP)₂]·DMF·3H₂O (<b>1</b>; NMP = <i>N</i>-methylpyrrolidone; DMF = <i>N</i>,<i>N</i>-dimethylformamide), has been prepared. It possesses a 3D framework and a strong ligand-based blue emission. <b>1</b> could be applied as a multifunctional chemical sensor for UO₂²⁺, PO₄^3-, and 2-thiazolidinethione-4-carboxylic acid (TTCA) with excellent selectivity, sensitivity, and anti-interference. In the 0-20 μM concentration range of UO₂²⁺, the quenching constant (<i>K</i>_SV) is 4.05 × 10⁴ M^-1 with a detection limit of 1.42 μM. Fluorescence enhancement was observed when PO₄^3- was added to the <b>1</b>-H₂O suspension. The slope of the linear relationship between the PO₄^3- concentration in the 0-35 μM concentration range and <i>I</i>/<i>I</i>₀ is 3.70 × 10⁴ M^-1 with a detection limit of 1.55 μM. When the TTCA concentration is lower than 20 μM, the fluorescence quenching constant <i>K</i>_SV is 1.77 × 10⁴ M^-1 with a detection limit of 3.25 μM, which approaches the values reported of the best CP-based sensing materials for TTCA up to now. Moreover, the fluorescence quenching or enhancement mechanism was also investigated.