Highly sensitive and recyclable sensing of Fe3+ ions based on a luminescent anionic [Cd(DMIPA)]2- framework with exposed thioether group in the snowflake-like channels.

Abstract An interesting chemically stable metal-organic framework, {(NC 2 H 8) 2 [Cd(DMIPA)]·xG} n (G=guest molecules of H 2 O and DMA, DMA= N , N -Dimethylacetamide) (1), featuring a 4-connected uninodal {42.64} topology and 18 Å × 18 Å snowflake-like channels along the c axis with exposed thioether groups, was assembled by employing a tetratopic polycarboxylate ligand of 5,5΄-thiobisophthalic acid (H 4 DMIPA). Ligand-based photoluminescence and solvent-dependent fluorescent intensities were exhibited in compound 1. Most strikingly, it showed remarkable sensitivity and selectivity toward Fe3+ ions under the presence of other metal ions. The photoluminescence quenching could be detected at a very low concentration of 1.62 ppm, and the maximum quenching efficiency was found to be 97.2% at 0.175 mM. Significantly, compound 1 can be recycled after use. The fluorescence intensity and quenching percentage of 1 exhibited very little changes after being used for ten successive cycles (I 0 = 6349–6093, and QP = 95.4–96.2%), indicating that 1 is a very promising MOFs-based sensor with remarkable sensitivity, selectivity, and reusability towards Fe3+ ions. Graphical abstract An interesting chemically stable metal-organic framework, {(NC 2 H 8) 2 [Cd(DMIPA)]·xG} n (G=guest molecules of H 2 O and DMA, DMA= N , N -Dimethylacetamide) (1), featuring a 4-connected uninodal {42.64} topology and 18 Å × 18 Å snowflake-like channels along the c axis with exposed thioether groups, was assembled by employing a tetratopic polycarboxylate ligand of 5,5΄-thiobisophthalic acid (H 4 DMIPA). fx1 Highlights • A chemically stable anionic framework with exposed thioether groups in the 18 Å × 18 Å snowflake-like channels was assembled. • It showed remarkable sensitivity and selectivity toward Fe3+ ions under the presence of other metal ions. • The photoluminescence quenching could be detected at a very low concentration of 1.62 ppm. • The maximum quenching efficiency was found to be 97.2% at 0.175 mM. [ABSTRACT FROM AUTHOR]