An acid-base resistant Zn-based metal-organic framework as a luminescent sensor for mercury(II)

A monocyclic organic ligand 5-aminoisophthalic acid (H2APA) with one amino and two carboxylic groups, has been employed to construct a stable Zn-based metal-organic framework, ZnAPA. It features a 3D supramolecular network containing the pores with a size of 8.2 ​Å and uncoordinated carboxylic oxygen atoms, exhibiting a pronounced fluorescence response (fast response, high sensitivity and selectivity) to Hg2+ ion over other metal ions in aqueous solution. The possible fluorescence-based sensing mechanism is also involved. Importantly, ZnAPA shows extraordinary acid-base resistant stability, highlighting its potential use for detection of Hg2+ in practical applications.