A Cd(II)-based Metal-Organic Frameworks (MOFs) with new topological net as multi-functional chemical sensor in detecting Fe3+, CrO42− and Cr2O72-

Abstract

In this study, a new MOFs {[Cd₃(HL)₆]}_n (1) was synthesized by using the 6-(pyridin-3′-yl) isophthalic acid (H₂L) and Cd(II) ions act as the building block via the solvothermal synthesis procedure, which have been fully characterized by single crystal X-ray diffraction, TGA, FT-IR, UV–visible spectroscopy and fluorescence experiments. The structure analysis reveal that 1 show a 2D layer structure based on a trinuclear [Cd₃(COO)₆N₆] secondary build blocks (SBUs). Interestingly, the half depronated organic ligand HL⁻ adopt three coordinated models with the center Cd(II) ions. Topological analysis show that the tri-nuclear SBUs and the organic ligands can be simplified as the 12- and 2- connect nodes, respectively. So the whole framework of 1 can be viewed as a new bimodal (2,12)-connect topological net with the point symbol of {4¹⁴.8³².12²⁰}. Additionally, the luminescence sensing explorations reveal that 1 exhibit remarkable selectivity for Fe³⁺, CrO₄²⁻ and Cr₂O₇²⁻ ions in aqueous solution, which provide a potential chemical sensor in detecting Fe³⁺ CrO₄²⁻ and Cr₂O₇²⁻ ions. The sensing mechanisms have also been discussed in detail.