Efficient detection of Cr3+ and Cr2O72− using a Zn(ii) luminescent metal–organic framework

Abstract

A luminescent metal–organic framework (LMOF), [Zn₂(TCBPDC)_0.5(H₂O)₂]_n·2.5H₂O·5DMF (1, DMF = N,N-dimethylformamide), has been synthesized by a solvothermal reaction and fully characterized by single-crystal X-ray diffraction, infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. Importantly, after the removal of guest molecules, 1a exhibited intense luminescence in the solid state and high sensitivity and selectivity to the Cr³⁺ and Cr₂O₇²⁻ ions in solutions. At the same time, the competition and cycling experiments demonstrated the luminescence response of 1a towards Cr³⁺ and Cr₂O₇²⁻, indicating good anti-interference ability and recyclability; this implied that 1a can be used as a potential probe for the detection of Cr³⁺ and Cr₂O₇²⁻. Additionally, the possible quenching mechanism is discussed.