A series of europium-based metal organic frameworks with tuned intrinsic luminescence properties and detection capacities

Abstract

Three new isostructural luminescent complexes [(CH₃)₂NH₂]₂[Eu₆(μ₃-OH)₈(BDC-NH₂)₆(H₂O)₆], [(CH₃)₂NH₂]₂[Eu₆(μ₃-OH)₈(BDC-F)₆(H₂O)₆] and [(CH₃)₂NH₂]₂[Eu₆(μ₃-OH)₈(BDC-NO₂)₆(H₂O)₆] have been synthesized based on [(CH₃)₂NH₂]₂[Eu₆(μ₃-OH)₈(1,4-NDC)₆(H₂O)₆] under solvothermal conditions. In addition, these Eu-MOFs possess tuned intrinsic luminescence properties and detection capacities for different analytes, such as Cr₂O₇²⁻, acetone and Fe³⁺. Here, these Eu-MOFs display distinct intrinsic luminescence properties because of the synergistic effect of donor groups and nonradiative vibrations, which are reflected in the lifetime, fluorescence quantum yield and emission intensity. Meanwhile, the detection experiments show that the one with the higher fluorescence quantum yield displays much more sensitive and efficient detection capacities for different kinds of analytes. Overall, this work indicated that tuning functional groups is vital to gain Eu-MOFs with good intrinsic luminescence properties, and make the detection capacities more sensitive and efficient.