2D Cd(II)–Lanthanide(III) Heterometallic–Organic Frameworks Based on Metalloligands for Tunable Luminescence and Highly Selective, Sensitive, and Recyclable Detection of Nitrobenzene

In this work, five novel 2D isostructural
Cd­(II)–lanthanide­(III)
heterometallic–organic frameworks [CdCl­(L)­EuxTby(H2O)­(DMA)]­(NO3)·3DMA (IFMC-36-EuxTby: x = 1, y = 0, IFMC-36-Eu; x = 0.6, y = 0.4, IFMC-36-Eu0.6Tb0.4; x = 0.5, y = 0.5, IFMC-36-Eu0.5Tb0.5; x = 0.4, y = 0.6, IFMC-36-Eu0.4Tb0.6; x = 0, y = 1, IFMC-36-Tb; H3L is 4,4′,4″-((2,2′,2″-(nitrilotris­(methylene))­tris­(1H-benzo­[d]­imidazole-2,1-diyl))­tris­(methylene))­tribenzoic
acid; IFMC = Institute of Functional Material Chemistry) have been
successfully synthesized by taking advantage of different molar ratios
of lanthanide­(III) (Ln­(III)) and metalloligands under solvothermal
conditions. Further luminescent measurements indicate that IFMC-36-EuxTby exhibits characteristic sharp emission
bands of Eu­(III) and Tb­(III), and the intensities of red and green
can be modulated correspondingly by tuning the ratios of Eu­(III) and
Tb­(III). Particularly, the solvent-dependent luminescent behavior
of IFMC-36-Eu shows a potential application in detection
of small-molecule pollutant nitrobenzene by significant fluorescence
quenching. Furthermore, IFMC-36-Eu displays preeminent
anti-interference ability and could be used for sensing in the systems
with complicated components. This is the first time that a d–f
heterometallic–organic framework can be investigated as a chemical
sensor for selective, sensitive, and recyclable detection of nitrobenzene.