Ancillary ligand enabled structural and fluorescence diversity in metal-organic frameworks: application for the ultra-sensitive detection of nitrofuran antibiotics

Fabrication of high-performance sensory materials for the ultra-sensitive detection of antibiotics in water is of significant importance for community health and environmental quality. Herein, two Zn(II)-based metal-organic frameworks, {[Zn-3(cbbi)(2)(bpe)(H2O)(6)]center dot 2H(2)O}(n) (FCS-4) and {[Zn-4(OH)(2)(cbbi)(2)(bpee)(H2O)(4)]center dot 2H(2)O}(n) (FCS-5), were prepared hydrothermally and employed as chemosensors for the ultra-sensitive detection of nitrofuran antibiotics. Interestingly, different spacers and flexibility in the nitrogen-donor ancillary ligands resulted in different topological structures and fluorescence properties. FCS-5 exhibited much better sensitivity for nitrofurazone and nitrofurantoin detection, with limits of detection (LOD) of 0.22 and 0.15 ppm, respectively. Furthermore, mechanism exploration indicated that photon-induced electron transfer plays a key role in the ultra-sensitive detection of nitrofuran antibiotics.