Uranyl Organic Framework as a Highly Selective and Sensitive Turn-on and Turn-off Luminescent Sensor for Dual Functional Detection Arginine and MnO4.

Five new uranyl coordination polymers were prepared by the hydrothermal method based on 5-nitroisophthalic acid (H2nip) as (UO2)(nip)(2,2'-bpy) (1), (H24,4'-bpy)·[(UO2)3(nip)4]·(4,4'-bpy) (2), (H2bpe)·[(UO2)0.5(nip)] (3), (H2 bpp)·[(UO2)2-(nip)3]·H2O (4), and (H2tmp)·[(UO2)(nip)2](5) [2,2'-bpy = 2,2'-bipyridine, 4,4'-bpy = 4,4'-bipyridine, bpe = 4,4'-vinylenedipyridine, bpp = 4,4' -trimethylenedipyridine, tmp = tetramethylpyrazine]. All of these synthesized complexes have been characterized by single crystal and powder X-ray diffraction, IR spectra, thermogravimetric analysis, elemental analysis, and luminescent properties. In particular, it is found that compounds 1 and 4 can be used as a luminescent sensor to efficiently detect arginine in aqueous solution by means of "turn-on"; the detection limits were 1.06 × 10-6 and 6.42 × 10-6 mol/L, respectively. Moreover, 4 can also be used as a bifunctional sensor for selective sensing of MnO4- anion by "turn-off". The detection limit of MnO4- in water was 1.79 × 10-6 mol/L; the Ksv was 1.88 × 104. The sensing effect of arginine in simulated grape juice samples and MnO4- in simulated river water samples was also investigated by this sensing system with high recovery. In addition, the possible mechanism of sensing arginine and MnO4- in the aqueous solution was discussed.