Two luminescent metal–organic frameworks for the sensing of nitroaromatic explosives and DNA strands

With a flexible aromatic ligand, bis-(3,5-dicarboxy-phenyl)terephthalamide (H4L), two metal–organic frameworks, Cd(L)·(HDMA)2(DMF)(H2O)3 (1) and Zn(L)·(HDMA)2(DMF)(H2O)6 (2), were synthesized using a solvothermal method. Both 1 and 2 possess a 3D open framework. These two compounds exhibit strong photoluminescence in suspensions, and their luminescence could be efficiently and selectively quenched by a series of nitroaromatics. Thus, 1 and 2 could be used as excellent luminescent probes for nitroaromatic explosives. Additionally, 1 and 2 could also be utilized as the sensing platforms for DNA strands, which is attributed to their different affinities for single- and double-stranded DNAs. With this method, 0.05 nM of target DNA could be detected, and the selectivity could be down to a single nucleotide mismatch. This work shows the potential of MOFs for the sensing of versatile chemicals.