RESUMEN
A water-stable three-dimensional (3D) metal-organic framework (MOF) of {[Tb(Cmdcp)(H2O)3]2(NO3)2·5H2O}n (1, H3CmdcpBr = N-carboxymethyl-(3,5-dicarboxyl)pyridinium bromide) has been synthesized and characterized. MOF 1 is highly emissive, giving rise to green luminescence that can be quenched by Fe3+ due to the partial overlap of its excitation spectrum with the absorption spectrum of Fe3+. The subsequent introduction of ascorbic acid (AA) leads to the reduction of Fe3+ into Fe2+, accompanied by the near-entire recovery of MOF 1 emission. The density functional theory (DFT) calculation results support the proposed mechanism. Such a sensing cycle is further transferable to urine and serum samples with a satisfactory near-quantitative recovery, highlighting its good potential in biologically relevant applications.
RESUMEN
We herein report an efficient Ag+ and S2- dual sensing scenario by a three-dimensional (3D) Cu-based metal-organic framework [Cu(Cdcbp)(bpea)] n (MOF 1, H3CdcbpBr = 3-carboxyl-(3,5-dicarboxybenzyl)-pyridinium bromide, bpea = 1,2-di(4-pyridinyl)ethane) shielded with a 5-carboxytetramethylrhodamine (TAMRA)-labeled C-rich single-stranded DNA (ss-probe DNA, P-DNA) as a fluorescent probe. The formed MOF-DNA probe, denoted as P-DNA@1, is able to sequentially detect Ag+ and S2- in one pot, with detection limits of 3.8 nM (for Ag+) and 5.5 nM (for S2-), which are much more lower than the allowable Ag+ (0.5 µM) and S2- (0.6 µM) concentration in drinking water as regulated by World Health Organization (WHO). The detection method has been successfully applied to sense Ag+ and S2- in domestic, lake, and mineral water with satisfactory recoveries ranging from 98.2 to 107.3%. The detection mechanism was further confirmed by molecular simulation studies.
