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

Abstract

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.