Synthesis, Structural Characterization of Two Cd/Co Complexes, and Dual Functional Fluorescence Sensing toward Fe³⁺ and \({\text{C}}{{{\text{r}}}_{2}}{\text{O}}_{7}^{{2 - }}\)

Two Cd/Co complexes, namely, {[Cd(Bcp)(2,2'-Bpy)(H₂O)]·H₂O}_n (I) and {[Co(Bce)(2,2'-Bpy)]}_n (II) (H₂Bcp = 1,2-bis(4-carboxy-phenoxy)ethane, H₂Bce = 1,3-bis(4-carboxy-phenoxy)propane, 2,2'-Bpy = 2,2'-bipyridine), have been synthesized and structurally elucidated by single crystal X-ray diffraction and thermogravimetric analysis (TGA). Both complexes feature 1D zig-zag chains decorated with 2,2'-Bpy, and the whole supramolecular architectures are stabilized by extensive π···π, C–H···π and H-bonding weak interactions. Complex I shows dual fluorescence sensing towards Fe³⁺ and \({\text{C}}{{{\text{r}}}_{2}}{\text{O}}_{7}^{{2 - }}\) . The fluorescence quenching mechanism was further investigated.