In Situ “One-Pot” Constructed Cd(II) Coordination Polymers for Luminescent Detection of Sulfadiazine

Abstract Two new Cd(II) coordination polymers were solvothermally fabricated with the organic ligands generated in situ by cyclocondensation. Under solvothermal conditions, 3,5-di(1H-imidazole-1-yl)benzaldehyde reacts with benzene-1,2-diamine to generate 2-(3,5-di(1H-imidazole-1-yl)phenyl)-1H-benzo[d]imidazole (HL) in situ. Based on the as-formed HL ligand, a Cd(II) coordination polymer {[Cd(HL)2(DMF)2](NO3)2}n (1) was obtained (DMF: N,N-dimethylformamide). Furthermore, by introducing thiophene-2,5-dicarboxylic acid (H2TDC) as an auxiliary ligand, a mixed-ligand Cd(II)-based coordination polymer [Cd2(HL)2(TDC)2]n (2) was constructed. The luminescent properties of complexes 1 and 2 were investigated. The results demonstrate that, compared to other antibiotics, both 1 and 2 exhibit high sensitivity and selectivity for the luminescence-based detection of sulfadiazine (SDZ), with detection limits (LOD) of 0.95 μM for 1 and 0.21 μM for 2, respectively. Notably, complex 1 enables ratiometric detection of SDZ and exhibits a distinct color change from greenish-blue to blue upon UV irradiation.