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 I4(1) and exhibit isostructural three-dimensional (3D) solid-state frameworks. Both complexes indicate characteristic sharp emission bands of Eu3+ or Tb3+ 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.