Two isostructural Ln-MOFs containing triazole groups as luminescent probes for efficient sensing of NACs and Fe3+

Two new isostructural 3D lanthanide metal-organic frameworks (Ln-MOFs), [Ln(2)(L)(3)(H2O)(2)]center dot 2H(2)O center dot 2DMF (1-Ln, Ln = Eu3+ and Tb3+, H2L = 5-triazole isophthalic acid) with uncoordinated triazole groups decorating the channels were successfully synthesized via solvothermal reaction. The uncoordinated triazole groups act as reserved host-guest binding sites to adjust the luminescence intensity of the Ln(3+) ion. Luminescence studies reveal that 1-Eu and 1-Tb as fluorescent probes both exhibit high sensitivities and excellent selectivities towards nitroaromatics (NACs) and Fe3+ in DMF system by luminescence quenching process. The quenching mechanisms were investigated through PXRD, DFT theory calculation, XPS, UV-vis and discussed in details.

Automated summary

Two new isostructural 3D lanthanide metal-organic frameworks (Ln-MOFs), [Ln(2)(L)(3)(H2O)(2)]center dot 2H(2)O center dot 2DMF (1-Ln, Ln = Eu3+ and Tb3+, H2L = 5-triazole isophthalic acid) were successfully synthesized via solvothermal reaction, with uncoordinated triazole groups decorating the channels. Luminescence studies reveal that 1-Eu and 1-Tb as fluorescent probes exhibit high sensitivities and excellent selectivities towards nitroaromatics (NACs) and Fe3+ in DMF system by luminescence quenching process. The quenching mechanisms were investigated through PXRD, DFT theory calculation, XPS, UV-vis and discussed in details.