Highly selective detecting Aspartic acid, detecting Ornidazole and information encryption and decryption supported by a heterometallic anionic Cd (II)-K (I)-MOF

Abstract

A highly stable heterometallic MOF, {[(Me₂NH₂)₂]·[Cd₂K₂(L)₂(H₂O)]}_n (H₄L = terphenyl-2, 2', 4, 4'-tetracarboxylic acid) (1), was synthesized. 1 featuring one-dimensional channels can efficiently detect Aspartic acid with a low limit of detection (LOD) value (2.5 μM). More interestingly, 1 can encapsulate Eu³⁺ and sensitize the visible-emitting characteristic fluorescence of Eu³⁺ in aqueous solution. Then, Eu³⁺@CdK-MOF is found to be an excellent fluorescence sensor for the detection of Ornidazole (ODZ) and the portable ODZ test paper is also successfully designed. Eu³⁺@CdK-MOF can also be used as fluorescent ink to write some words. The words can be hidden when treated with acid vapor and then the words can be restored when treated with alkaline vapor. More importantly, the hidden information can be read repeatedly. Therefore, this reversible light-emitting and reusable property have great potential for development in information encryption and decryption and information storage.

Keywords: Fluorescence sensor; Fluorescent ink; Luminescent materials; Metal-organic framework; Test paper.