Three robust luminescent Cd(II) coordination polymers as multi-responsive fluorescent sensors for Cu2+, Hg2+, levofloxacin, and acetylacetone in water

•Three ternary Cd(II)-CPs derived from new ligands were synthesized and characterized.•1 − 3 are the first multi-responsive sensors for Cu2+, Hg2+, levofloxacin, and acetylacetone.•1 − 3 demonstrated high sensitivity and selectivity in sensing these analytes.•The luminescent sensing mechanisms were discussed in detail. Employing coordination polymers (CPs) developing effective organic contaminants and heavy metal ions luminescent detection systems is an ongoing challenge. Three ternary Cd(II) CPs namely [Cd(MIP)(L)0.5(H2O)]n (1), [Cd2(TPA)2(L)(H2O)]n (2), and [Cd2(DCTP)2(L)(H2O)]n (3), (L = 1,6-bis(2-((1H-imidazol-1-yl)methyl)-1H-benzo[d]imidazol-1-yl)hexane, H2MIP = 5-methylisophthalic acid, H2TPA = terephthalic acid, and H2DCTP = 2,5-dichloroterephthalic acid) containing new L ligands, were hydrothermally synthesized and characterized. 1 displays a (4,4)-connected 4,4L28 layer and further extended into the 3D supramolecular framework via π−π stacking interactions. 2 exhibits a (4,4,5)-connected trinodal network with the point symbol of {42.5.62.8}{42.52.72}{42.53.62.73}2. 3 takes on a (3,5,6)-connected framework with the point symbol {3.42.52.7}{3.82}2{33.44.5.62.82.92.10}2. 1 − 3 show highly good thermal stability, and highly acid-base tolerance. The limits of detection (LOD) of 1 − 3 were calculated as follows: for Cu2+, the LODs are 8.92 × 10−8, 5.74 × 10−7, and 9.37 × 10−8 mol L−1, respectively; for Hg²⁺, the LOD values are 3.73 × 10−7, 5.22 × 10−7, and 8.45 × 10−7 mol L−1, respectively. Regarding levofloxacin (LEV), the LODs for 1 − 3 were found to be 5.11 × 10−8 mol L−1, 2.45 × 10−8 mol L−1, and 8.54 × 10−8 mol L−1, respectively. Finally, for acetylacetone (acac), the LODs of 1 − 3 are 5.53 × 10−6, 5.66 × 10−6, and 1.23 × 10−6 mol L−1, respectively. 1 − 3 represent the first examples of exceptional multi-responsive sensing platforms for the detecting of Cu2+, Hg2+, LEV, and acac with high sensitivity, outstanding anti-interference abilities, and low LODs. The possible sensing mechanisms were investigated in detail. Three new ternary Cd(II)-based coordination polymers were hydrothermally synthesized and characterized, which can act as exceptional multi-responsive sensing platforms for the detecting of Cu2+, Hg2+, levofloxacin, and acetylacetone with high sensitivity, outstanding anti-interference abilities, and low limit of detections. The possible sensing mechanisms were investigated in detail. [Display omitted]