Two dimethylphenyl imidazole dicarboxylate-based lanthanide metal–organic frameworks for luminescence sensing of benzaldehyde

Two novel dimethylphenyl imidazole dicarboxylate-based lanthanide(III)-organic frameworks, [Ln(H2DMPhIDC)3(H3DMPhIDC)]n (Ln = Eu (1), Tb (2); H3DMPhIDC = 2-(3,4-dimethylphenyl)-1H-imidazole-4,5-dicarboxylic acid) have been synthesized under hydrothermal conditions. Single crystal X-ray diffraction analyses revealed that polymers 1 and 2 crystallize in the tetragonal space group I4₁ and exhibit isostructural three-dimensional (3D) solid-state frameworks. Both complexes indicate characteristic sharp emission bands of Eu(3+) or Tb(3+) ions, which are selectively sensitive to benzaldehyde-based derivatives (benzaldehyde, m-methylbenzaldehydes, m-carboxylbenzaldehyde and m-hydroxybenzaldehyde). These properties make both complexes potential fluorescence sensors for these chemicals.