Two stable 3D porous metal-organic frameworks with high selectivity for detection of PA and metal ions

Abstract Two new coordination polymers, {[Zn4(DPBT)2(BDC)4]·(H2O)·2(DPBT)}n (1), {[Cd2(DPBT)2(BDC)2]·(DMA)}n (2), have been obtained from the self-assembly of the heterocycle ligand DPBT with different d10 metal ions, in the presence of BDC2− coligand. Interestingly, the emission spectra exhibit that both compounds possess fluorescent turn-on or turn-off sensing behavior for different metal ions. Compared with the other metal ions, Fe3+ shows significant quenching effect and Al3+, Cr3+show enhancement effect on the fluorescence intensity for 1. The fluorescence intensity of 2 progressively enhance with the increase of concentrations of Al3+, Cr3+ and Pb2+ ions. In addition, the photofluorescent titration upon the addition of nitrate salts to 1's and 2's emulsions were also conducted. They are developed as highly selective and sensitive probes for detection of PA in DMF solution based on fluorescence quenching with a detection limit of 0.01 μM and 0.1 μM, respectively.