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

• A heterometallic anionic Cd (II)-K (I)-MOF was synthesized. • Cd (II)-K (I)-MOF showed high selectivity and sensitivity to Aspartic acid. • Cd (II)-K (I)-MOF can encapsulate Eu 3+ and sensitize characteristic fluorescence of Eu 3+ . • Eu 3+ @CdK-MOF can detect Ornidazole with low detection limit and the ODZ test paper was also successfully designed. • Eu 3+ @CdK-MOF has great potential in information encryption and decryption and information storage. A highly stable heterometallic MOF, {[(Me 2 NH 2 ) 2 ]·[Cd 2 K 2 (L) 2 (H 2 O)]} n (H 4 L = 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 Eu 3+ and sensitize the visible-emitting characteristic fluorescence of Eu 3+ in aqueous solution. Then, Eu 3+ @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. Eu 3+ @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.