A pillar-layer metal-organic framework as a turn-on luminescent sensor for highly selective and sensitive detection of Zn(II) ion

The intriguing architectures of metal-organic frameworks (MOFs), makes them an emerging class of promising materials in various application fields ranging from gas adsorption to sensing. In the present work, a three-dimensional Zn-based MOF, Zn-2(BDC)(2)(DABCO), (H2BDC = 1,4-benzene dicarboxylic acid, DABCO = 1,4-diazabicyclo[2.2.2]octane) was prepared and its sensing behavior to metal ions was investigated by fluorescence assays. Our results show that the luminescence intensity of Zn-2(BDC)(2)(DABCO) is strongly sensitive to Zn2+ ions. The effects of selectivity, initial concentration, the limit of detection, response time and regeneration were studied in the case of Zn2+ detection operations. The linear response to Zn2+ was obtained across the concentration range of 50-200 mu M with the detection limit of 0.7 mu M. The sensor also displayed excellent performance in selectivity for Zn2+ over other metal ions including Fe3+, MN2+, CU2+, AS(3+), Ni2+, Pb2+, CO2+, Al3+ and Cd2+ ions. The luminescence enhancement and recovery cycle were reiterated multiple times without much effect on the sensitivity. All the above features showed that this sensor as a sensing platform holds great potential for detection of Zn2+ with a response time of <1 min that has been rarely reported.