Two stable cobalt(II) coordination polymers as dual-functional fluorescent sensors for efficient detection of Zn2+/Cu2+ ions and norfloxacin

The detection of metal cations and antibiotics based optical sensing material in the human body and environment is very vital. Two new ternary Co(II) coordination polymers, namely {Co(L)0.5(BTCA)0.5(H2O)]·3H2O}n (1) and [Co(L)(HIPA)·H2O]n (2) (H4BTCA ​= ​1, 2, 3, 4-butanetetracarboxylic acid, H2HIPA ​= ​5-hydroxyisophthalic acid), were constructed and characterized from the rarely reported semi-rigidity 1,4-bis(thiabendazole-1-yl)-2-butene (L) N-donor linker. 1 displays a 2D 3,4-connected 3,4L13 layer, while 2 features a 1D straight chain, and further extends into a 2D supramolecular network via O–H⋯O interactions. 1 and 2 exhibit superior chemical and thermal stability. 1 and 2 can be used as efficient sensors toward Zn2+ ions via turn-on fluorescent enhancing and Cu2+ ions by a turn-off fluorescent quenching effect, separately. They were also applied as probes to detect norfloxacin with high sensitivity, selectivity, and recyclability by fluorescence quenching. The luminescent sensing mechanisms for these analytes were speculated. 1 and 2 are the first dual-functional sensors for the detection of Zn2+/Cu2+ ions and norfloxacin.