Two New Luminescent Cd(II)-Metal-Organic Frameworks as Bifunctional Chemosensors for Detection of Cations Fe3+, Anions CrO42-, and Cr2O72- in Aqueous Solution

Two new luminescent Cd(II)-metal-organic frameworks (MOFs), {[Cd(L)(BPDC)]center dot 2H(2)O)}(n) (1) and {[Cd(L)(SDBA)(H2O)]center dot 0.5H(2)O}(n) (2) [L = 4,4'-(2,5-bis(methylthio)-1,4-phenylene)dipyridine, H2BPDC = 4,4'-biphenyldicarboxylic acid, H(2)SDBA = 4,4'-sulfonyldibenzoic acid], have been solvothetmally 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.