Metal-organic frameworks constructed from trivalent lanthanide nodes (Eu3+, Tb3+, and Dy3+) and thiophenethio-functionalized linker with photoluminescent response selective towards Ag+ ions

Three metal-organic frameworks based on three lanthanide (Ln) ions (Eu3+ for 1, Tb3+ for 2, Dy3+ for 3) and thiophenethio-functionalized linker (2,2',5,5'-tetrafluoro-3,3',6,6'-tetrakis(2-thiophenethio)-4,4'-biphenyl dicarboxylic acid, H2BPD-4F4TS) were prepared. Out of these MOFs, 1 demonstrated at most 8-time photo-luminescence enhancement towards Ag+ ions selectively. With higher quantum yield and longer excited-state lifetime after introduction of Ag+ ions, the emission enhancement in 1 is rationalized as the result of strength-ened 'antenna effect'. 1 represents the first example of Ln-MOFs utilizing Eu3+ ions as nodes and thiophenethio-functionalized linkers as luminescent probes for selective Ag+-ion sensing.

Automated summary

Three metal-organic frameworks were synthesized using lanthanide ions (Eu3+ for 1, Tb3+ for 2, Dy3+ for 3) and a thiophenethio-functionalized linker. Among them, 1 showed the highest enhancement of photo-luminescence towards Ag+ ions, attributed to the strengthened 'antenna effect' after introduction of Ag+ ions. This study represents the first example of using Eu3+ ions as nodes and thiophenethio-functionalized linkers for selective sensing of Ag+ ions in Ln-MOFs.