Three Novel Alkaline-Earth Ca(II)/Mg(II)/Ba(II)-Based Coordination Polymers as Fluorescent Probes for Nor and Pef Antibiotic Detection

Three new alkaline-earth Ca(II)/Mg(II)/Ba(II)-based coordination polymers (CPs) with unique structures, namely, {[Ca 2 (L1)(H 2 O)]·1.5H 2 O} n ( 1 ), [Mg(L1) 0.5 (phen)(H 2 O)] n ( 2 ), and {[Ba 2 (L2)(H 2 O) 4 ]·H 2 O} n ( 3 ) (H 4 L1 = 1,2-di((3,5-dicarboxy-1 H -pyrazol-1-yl)methyl)benzene, H 4 L2 = 1,3-di((3,5-dicarboxy-1 H -pyrazol-1-yl)methyl)benzene, and phen = 1,10-phenanthroline), were synthesized by hydrothermal method. The three coordination polymers were characterized in detail by single-crystal X-ray diffraction, elemental analyses, infrared spectra, thermogravimetric analyses, and powder X-ray diffraction. The internal molecular interaction forces were also analyzed by Hirshfeld surface analyses. Compounds 1 – 3 were used as fluorescent probes for the detection of the antibiotics norfloxacin (Nor) or pefloxacin (Pef). The results demonstrated that Nor produced a fluorescence turn-on effect for compounds 1 and 2, and Pef produced a fluorescence turn-on effect for compound 3 . The detection limits of compounds 1, 2, and 3 were 0.078, 1.68, and 2.45 μM, respectively, which indicated that these three compounds are excellent fluorescent probe materials.