A multiresponsive luminescent probe of antibiotics, pesticides, Fe3+ and ascorbic acid with a Cadmium(II) metal-organic framework

Abstract

A novel two-dimensional (2D) cadmium-based metal-organic framework [Cd2(HDDB)(bimpy)(NMP)(H2O)]·3H2O (1) (H5DDB = 3,5-di(2′,4′-dicarboxylphenyl)benozoic acid and bimpy = 3,5-bis(1-imidazolyl)pyridine) has been constructed by solvothermal method, which exhibits good water stability, pH stability and excellent photoluminescence properties. Complex 1 reveals a fluorescence turn-off behaviour towards nitrofuran/nitroimidazole antibiotics and DCN pesticide due to PET (photoinduced electron transfer) and FRET (fluorescence resonance energy transfer). Interestingly, complex 1 can be designed as an “on-off-on” fluorescence probe to detect Fe3+ ion and ascorbic acid (AA). The fluorescence of complex 1 can be quenched by Fe3+ ion to form a Fe3+@1 hybrid system, which can be ascribed to the FRET process and the week interaction between Fe3+ and 1. Then, after gradually adding AA into Fe3+@1 system, the fluorescence intensity of Fe3+@1 fluorescence-silent system was recovered (turn on). The possible fluorescence turn-on mechanism is the elimination of FRET process between Fe3+ and complex 1. This work represents the first example of recognition of nitrofuran/nitroimidazole antibiotics, DCN pesticide, Fe3+ ion and AA based on a MOF material in aqueous solution.