Multi-component hybrid soft ionogels for photoluminescence tuning and sensing organic solvent vapors

This paper tries to prepare soft ionogels through the carboxyl ion liquid (IM⁺Br^-) as double chemical linker connecting both Bio-MOF-1 (Zn₈(ad)₄(BPDC)₆O·2Me₂NH₂, BPDC=biphenyl-4,4'-dicarboxylate, Ad = adeninate) and lanthanide complexes. Among anionic Bio-MOF-1 interacts with IM⁺Br^- through cation exchange (IM⁺) to form BMOF-IM and lanthanide ions are further introduced through the coordination to the carboxylic group of IM⁺ together with Phen (1,10-phenanthroline) as assistant ligand for Ln³⁺ (Ln = Eu, Tb or Eu/Tb). The resulting multi-component hybrid ionogels (Phen-Ln-IM@BMOF) are prepared and characterized by PXRD, FTIR, TGA and mechanical properties by compression experiment, respectively. The photophysical properties of these hybrid systems are studied in details. By controlling the composition of different Ln³⁺ cations in IM@BMOF, the luminescent color of them can be tuned and the white light output can be realized. Furthermore, with careful adjustment of the excitation wavelength, the color of the luminescence can be modulated. Eventually we obtain luminescence trichromatic (Phen-Eu/Tb-IM@BMOF) white-light-emitting materials. Moreover, we try to choose Phen-Eu-IM@BMOF hybrid system for the detection of organic volatile substances, which shows the apparent luminescence quenching effect on ammonia for high sensitivity of sensing.