Introduction of Organic Dyes into Cadmium(II) MOF for Tunable Light Emission and Highly Sensitive Probing Antibiotics

Abstract A honeycomb porous cadmium(II) metal–organic framework {[Cd(L)(H 2 O)] ⋅ NMP ⋅ 5H 2 O} n ( 1 , H 2 L=1‐(4‐carboxyphenyl)‐1H‐pyrazole‐3‐carboxylic acid and NMP=1‐methyl‐2‐pyrrolidinone) was obtained using the solvothermal method. The luminescent molecules rhodamine B (RhB) and fluorescein (FL) were encapsulated in 1 using the immersion method to prepare RhB@1 and FL@1 dual emission composites. Additionally, a series of RhB x /FL 1‐x @1 composites with varying luminescence properties were generated by altering the molar ratio of RhB to FL. Furthermore, the photoluminescence of RhB@1 and FL@1 was demonstrated to be caused by photoelectron transfer and fluorescence resonance energy transfer from 1 to the encapsulated guest module. Notably, RhB@1 showed the considerable improvement in fluorescence selectivity and detection limit (10 −6 M) for metronidazole and dimetronidazole with remarkable recyclability.