A dual-functional Co(II) coordination polymer luminescent sensor: turn-off sensing acetylacetone and rare turn-on detection of ascorbic acid

Abstract One new Co(II) coordination polymer was prepared by the hydrothermal method based on a semi-rigid tricarboxylate acid, 4-(2′,3′-dicarboxylphenoxy) benzoic acid (H3L) as [H2bpe][Co(HL)2(bpe)(H2O)2]·(H2O)4 (1) (bpe = 1,2-bis(4-pyridyl) ethylene). This compound has been characterized by single crystal and powder X-ray diffraction, elemental analysis, IR spectra, thermogravimetric analysis, and fluorescent properties. In particular, it is found that compound 1 possesses excellent chemical stability. More importantly, this material could act as a novel “turn-on” fluorescent probe for highly selectively sensitizing ascorbic acid (AA) and “turn-off” sensor for recognizing acetylacetone (Hacac) in the aqueous phase. Both proposed sensing systems showed excellent performance with high sensitivity and selectivity as well as good reusability. The detection limits are as low as 2.60 nM and 57.5 μM, respectively. In addition, the possible mechanism were detailedly discussed.