Two 3D Isostructural Ln(III)-MOFs: Displaying the Slow Magnetic Relaxation and Luminescence Properties in Detection of Nitrobenzene and Cr₂O₇^2–

Abstract

Two new three-dimensional isostructural lanthanide metal–organic frameworks (Ln(III)-MOFs), [LnL(H 2 O) 3 ]·3H 2 O·0.75DMF ( 1-Ln; Ln = Dy(III) and Eu(III) ions, H 3 L = biphenyl-3′-nitro-3,4′,5-tricarboxylic acid, DMF = N, N ′-dimethylformamide), were synthesized and characterized. The appearance of temperature-dependent out-of-phase (χ″ M ) signal reveals that complex 1-Dy displays slow magnetic relaxation behavior with the energy barrier (Δ U eff ) of 57 K and a pre-exponential factor (τ 0 ) of 3.89 × 10 –8 s at 1200 Oe direct current field. The luminescence explorations demonstrated that 1-Eu exhibits high quenching efficiency and low detection limit for sensing nitrobenzene and Cr 2 O 7 2– . Meanwhile, the fluorescence intensity of the quenched 1-Eu samples will be resumed after washing with DMF or water, indicating that 1-Eu may be used as a highly selective and recyclable luminescence sensing material for sensing nitrobenzene and Cr 2 O 7 2– anion.