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

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]DMF3H2O (1; NMP = N-methylpyrrolidone; DMF = N,N-dimethylformamide), has been prepared. It possesses a 3D framework and a strong ligand-based blue emission. 1 could be applied as a multifunctional chemical sensor for UO22+, PO43-, 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 (KSV) is 4.05 × 104 M-1 with a detection limit of 1.42 μM. Fluorescence enhancement was observed when PO43- was added to the 1-H2O suspension. The slope of the linear relationship between the PO43- concentration in the 0-35 μM concentration range and I/I0 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 KSV 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.