Two coordination polymers as multi-responsive luminescent sensors for the detection of UO22+, Cr(vi), and the NFT antibiotic

Two coordination polymers, namely {[Cd3(TIYM)2(5-SASS)2(H2O)2]·H2O}n (1) and {[Zn2(TIYM)(5-SASS)(μ2-OH)]·5H2O}n (2), were assembled using a mixed ligand strategy with the semi-rigid linker tetrakis(imidazol-1-ylmethyl)methane (TIYM) and 5-sulfoisophthalic acid sodium salt (5-SASS). Luminescence studies reveal that compounds 1 and 2 show strong fluorescence and exhibit efficient luminescence quenching in detecting UO22+ cations, Cr2O72−/CrO42− anions, and the NFT antibiotic in aqueous media, and can thus serve as promising sensors. The detection limits of compounds 1–2 are 1.96 × 10−4/1.36 × 10−4 M for UO22+ cations, 6.53 × 10−5/5.41 × 10−5 M for Cr2O72− anions, 2.29 × 10−4/1.04 × 10−4 M for CrO42− anions, and 5.62 × 10−5/4.74 × 10−5 M for the NFT antibiotic, respectively, indicating that the two CPs are promising multi-functional luminescent sensors. Additionally, the possible mechanisms for luminescence quenching have been investigated using spectral overlap experiments and DFT calculations.