Luminescence Changeable CO₂‐Storage Cylinder: Triple‐Stranded Helical Eu(III)/Tb(III) Fluorinated MOFs with Amide Linkers

Triple-stranded helical lanthanide MOFs with CO₂ adsorption properties were investigated. Lanthanide MOFs ([Eu_0.1Tb_0.9(hfa)₃(dpa)]_n) are composed of lanthanide luminophores (Eu(III) and/or Tb(III) ions), fluorinated antenna ligands (hfa: hexafluoroacetylacetonate), and polyamide-type linker ligands (dpa: 4-(diphenylphosphoryl)-N-(4-(diphenylphosphoryl)phenyl)benzamide). The cylindrical structure was characterized by single-crystal X-ray analysis, thermogravimetric analysis, and gas adsorption measurements. The inner surfaces of the cylindrical channels were covered with the fluorine atoms of the hfa ligands. The emission intensity ratio (I_Eu/I_Tb) in [Eu_0.1Tb_0.9(hfa)₃(dpa)]_n is affected by the CO₂ gas adsorption behavior. The change in I_Eu/I_Tb value was caused by the intermolecular interactions between the CO₂ gas molecules and the fluorinated ligands, resulting in an electronic structural change of the lowest triplet excited state in the photosensitized hfa ligands.