ABSTRACT
A new class of Ln-MOFs (Ln = Eu, Tb, Eu/Tb, Sm) are synthesized through a post-synthetic modification of the parent MOF, UMCM-NH2. The luminescence spectra of Eu-MOF, Tb-MOF and Eu/Tb-MOF exhibit the characteristic emission bands of ligands and corresponding Ln3+, particularly Eu3+. Multi-color luminescence could be modulated by adjusting the excitation wavelength of the Eu-MOF and Tb-MOF. What's more, white-light emission may be realized by co-doping the Eu3+ and Tb3+ due to the synergistic contribution of the three luminescence centers. In addition, the Eu-MOF is selected as a luminescence sensor to explore the potential of sensing organic small molecules. Most interestingly, it exhibits a highly selective, sensitive and rapid response to THF, which could be distinguished easily by the naked eye under UV-light irradiation. Consequently, Eu-MOF is a promising candidate as the "turn on" fluorescent probe for detecting THF that has been rarely reported.
ABSTRACT
A Zr-based metal-organic framework (Zr-MOF) which has free carbonyl groups is synthesized successfully through mix-ligand strategy. Subsequently, Tb3+ is encapsulated into a Zr-MOF by postcoordinated modification. The Tb3+@Zr-MOF exhibits the characteristic emission of Tb3+ because of efficient sensitization through antenna effects. The Tb3+@Zr-MOF is further developed as a novel "turn-on" fluorescent probe to detect fluoride ions in aqueous solution. The results show that Tb3+@Zr-MOF exhibits excellent selectivity, high stability, low detection limits, and good anti-interference for sensitizing fluoride ions. In addition, the possible sensing mechanism that the induced luminescence properties may be attributed to Lewis acid-base interactions is discussed.