Fabrication of a Stable Cd-MOF as a Promising Luminescence Sensor for Selectively Distinguishing 3,4-Dichlorobenzamine and 3,5-Dichlorobenzamine in Real Urine and River Water Systems

In this paper, by the self-assembly of a symmetric tetracarboxylic ligand, H4mtptc (5′-methyl-[1,1′:3′,1″-triphenyl]-3,3″,5,5″-tetracarboxylic acid) and Cd(NO3)2·4H2O, a 2D Cd-based metal–organic framework, [Cd2(mtptc)(H2O)4(C5H5N)2]·DMF·H2O (Cd-MOF, compound 1) was developed successfully using a solvent thermal synthesis method. The X-ray diffraction experiment revealed that 1 featured outstanding acid–base stability and solvent stability. Moreover, considering the luminescence capacity and potential hazards of 3,4-dichlorobenzamine (3,4-DCA) and 3,4-dichlorobenzamine (3,5-DCA), luminescence-sensing measurements of 1 for 3,4-DCA/3,5-DCA were performed. The results indicate that 1 exhibited a distinguished potential for the selective detection of 3,4-DCA/3,5-DCA through luminescence quenching effects, with quenching constants (Ksv) and limits of detection (LOD) of 2.72 × 104 M–1 and 0.71 μM for 3,4-DCA and 2.27 × 104 M–1 and 0.65 μM for 3,5-DCA in DMF-H2O solution. Besides, the exploration of the sensing capacities under practical conditions confirmed that the sensing performance of 1 in urine samples and real river water from the Tuhai River was comparable to that in DMF-H2O solution, further proving the promising potential of compound 1 as a reliable luminescence sensor for 3,4-DCA/3,5-DCA.