Two isostructural Ln(3+)-based heterometallic MOFs for the detection of nitro-aromatics and Cr2O72-

Luminescent MOFs (LMOFs) are increasingly regarded as potential chemical sensors with the advantages of high sensitivity and selectivity for detecting various analytes. Here, two isostructural Ln(3+)-based heterometallic MOFs (In/Eu-CBDA and In/Tb-CBDA) based on the tetracarboxylic acid ligand [CBDA = 5,5'-(carbonylbis(azanediyl))-diisophthalic acid] have been successfully synthesized. According to the hard and soft acid-base (HSAB) theory, the compounds exhibit excellent stability, which is conducive to the application of practical properties. Therefore, In/Eu-CBDA and In/Tb-CBDA were used in the detection of nitro-aromatics and anions. The results showed that they have the ability to detect 1,4-dinitrobenzene and Cr2O72- with high selectivity and sensitivity. In particular, Cr2O72- on In/Tb-CBDA is detected with a quenching constant of 1.72 x 10(4) M-1 and a detection limit of 8.72 x 10(-6) M-1 in the water environment, which shows that it can be used as a promising candidate luminescent sensor for application in the detection of Cr2O72- in wastewater.