Luminescent sensing of Fe3+ and K+ by three novel imidazole dicarboxylate-based MOFs

In this paper, three luminescent metal–organic frameworks, namely: [Zn(p-IPhHIDC)]_n (1), {[Cd(p-IPhIDC)(H₂O)]·CH₃OH}_n (2) and [Zn(p-TIPhHIDC)]_n (3), bearing two novel substituted imidazole dicarboxylate ligands, 2-(p-N-imidazol-1-yl)-phenyl-1H-imidazole-4,5dicarboxylic acid (p-IPhH₃IDC) and 2-p-(1H-1,2,4-triazol-1-yl)-phenyl-1H-imidazole-4,5dicarboxylic acid (p-TIPhH₃IDC), have been prepared and characterised through infrared spectra, X-ray powder diffraction, elemental analyses, thermogravimetric analyses and single-crystal X-ray diffraction. Ignoring the free methanol molecule and coordinated water in 2, 1–3 are similar structures. Moreover, the luminescent properties of the MOFs have been explored. It was found that MOFs 1 and 2 show good luminescent sensing of Fe³⁺ in varying degrees, and 3 of K⁺.