A Pillar-Layered Zn-LMOF with Uncoordinated Carboxylic Acid Sites: High Performance for Luminescence Sensing Fe³⁺ and TNP

Abstract

By using the mixed-linker strategy, a new pillar-layered luminescence Zn-LMOF (JLU-MOF71) ([Zn₂Na₂(TPHC)(4,4-Bipy)(DMF)]·8H₂O) (TPHC = [1,1':2',1″-terphenyl]-3,3″,4,4',4″,5'-hexacarboxylic acid, 4,4-bipy = 4,4-bipyridine, DMF = N, N-dimethylformamide) was successfully synthesized and structurally characterized. JLU-MOF71 is constructed by the 4,4-bipy pillars and 2D layers which consist of Zn²⁺ and TPHC ligands, and displays a rare fsh topology. Benefiting from the uncoordinated carboxylate sites in the framework, JLU-MOF71 not only can sensitively detect trace amounts of individual Fe³⁺ and 2,4,6-trinitrophenol (TNP) through luminescence quenching but also exhibits high selectivity when other competing analytes exist. Besides, TNP can also be effectively monitored with the help of the shifting direction of luminescent spectra (red shift) which has rarely been reported before. On the basis of the aforementioned, JLU-MOF71 can be considered as a potential luminescence sensor for detecting Fe³⁺ and TNP.