A porous Cd-based metal-organic framework for sensitive and selective detection of aspartic acid/Ag+ in aqueous medium

Abstract The development of a fast and stable luminescence detection method is of great significance to people's health and the protection of the ecological environment. In this work, a porous three-dimensional (3D) Cd-based metal-organic framework (MOF1) has been synthesized by the reaction of tri(p-carboxyphenyl)phosphane oxide (H3L) and 1,4-bis(pyrid-4-yl)benzene (1,4-bpb) with Cd2+ ions based on the mixed-ligand strategy, and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and scanning electron microscope (SEM), etc. The luminescence experiments of MOF1 for amino acids and cations showed that MOF1 has highly sensitive and selective recognition for aspartic acid/Ag+ in aqueous medium. Meanwhile, the recognition mechanism of MOF1 for aspartic acid/Ag+ was analyzed by a series of experiments, the results indicate that the energy gap between HOMO energy values of H3L and aspartic acid/Ag+ is recognition impetus of MOF1 for aspartic acid by enhancement luminescence and for Ag+ by luminescence quenching, the sensing processes of MOF1 for aspartic acid and Ag+ ions are dynamic and static respectively by fluorescence lifetimes. Furthermore, the cycle and anti-interference experiments indicate that MOF1 has good luminescence stability and high sensing selectivity for aspartic acid and Ag+. The above results indicate that MOF1 has potential applications in recognizing aspartic acid and Ag+ in aqueous medium.