Metal-induced assembly of three novel MOFs: Displaying the sensitive fluorescence sensing and rapid dye adsorption properties

Three novel metal-organic frameworks (MOFs) formulated as [Cd(5-mipa)(bpe)1.5·0.8DMF]n (1), [Zn(5-mipa)(bpe)]n (2), and {[Ni(5-mipa)(bpe)]·0.4IPA}n (3) (IPA = iso-propyl alcohol) were successfully obtained via solvothermal reaction between the corresponding transition metal nitrates and 5-methylisophthalic acid (5-H2mipa), 1,2-bis(4-pyridyl)ethylene (bpe). All compounds were adequately characterized, and their structures were verified by single-crystal X-ray diffraction. The solid-state luminescence properties of three complexes were investigated at ambient temperature. 1 shows high sensitivity for Fe3+ and nitrobenzene by the luminescence quenching effect with the low detection limit 7.0 × 10−5 M and 6.84 × 10−5 M, respectively, and its mechanisms have been studied in detail. Additionally, the selective adsorption of compounds 2 and 3 to anionic dyes (Methyl Orange (MO) and Congo Red (CR) and cationic dye Methylene Blue (MB) were examined. The results demonstrated that 2 and 3 showed good adsorption properties for MO and CR anionic dye molecules.