A new stable luminescent Cd(ii) metal–organic framework with fluorescent sensing and selective dye adsorption properties.

A new luminescent metal–organic framework, {[Cd₃(HL)₂(H₂O)₃]·3H₂O·2CH₃CN}_n (1) (H₄L = 1-(3,5-dicarboxylatobenzyl)-3,5-pyrazole dicarboxylic acid), has been synthesized by solvothermal reaction and characterized by infrared spectroscopy, powder X-ray diffraction, thermogravimetry measurements and so on. 1 shows a new trinodal (4,4,6)-connected topology. Importantly, 1 displays intense luminescence in the solid state and high luminescent sensitivity and selectivity for Fe³⁺, CrO₄²⁻ and Cr₂O₇²⁻ ions in aqueous solution, making it a potential probe for detecting these substances. The quenching mechanisms are also further discussed in detail. In addition, further research on the adsorption of dyes shows that 1 can selectively adsorb Congo red dye from other dye molecules. [ABSTRACT FROM AUTHOR]