Two New Luminescent Cd(II)-Metal–Organic Frameworks as Bifunctional Chemosensors for Detection of Cations Fe³⁺, Anions CrO₄^2–, and Cr₂O₇^2– in Aqueous Solution

Abstract

Two new luminescent Cd(II)-metal–organic frameworks (MOFs), {[Cd(L)(BPDC)]·2H2O}n (1) and {[Cd(L)(SDBA)(H2O)]·0.5H2O}n (2) [L = 4,4′-(2,5-bis(methylthio)-1,4-phenylene)dipyridine, H2BPDC = 4,4′-biphenyldicarboxylic acid, H2SDBA = 4,4′-sulfonyldibenzoic acid], have been solvothermally synthesized using Cd2+ ion and L ligand in the presence of auxiliary ligands and characterized by infrared spectroscopy, elemental analysis, powder X-ray diffraction, and thermogravimetry measurement. Topological analyses reveal that MOF 1 is a 6-connected 3-fold interpenetrating pcu network, and MOF 2 is a new 4-connected 2-fold interpenetrating network. Fluorescence titration, cyclic and anti-interference experiments demonstrate that MOFs 1 and 2 both are excellent probes for Fe3+, CrO42–, and Cr2O72–. The mechanisms of quenching are also deeply studied.