Two unique lanthanide–organic frameworks based on biphenyl-2,3,3′,5′-tetracarboxylic acid: Syntheses, crystal structures and luminescence properties

The reactions in mixtures of lanthanide oxides and biphenyl-2,3,3′,5′-tetracarboxylic acid, in the presence of aqueous solution, result in two interesting lanthanide–organic coordination polymers, formulated as{[Eu(Hbptc)(H2O)4]·H2O}n (1) and [Sm(Hbptc)(H2O)3]}n (2), (H4bptc = biphenyl-2,3,3′,5′-tetracarboxylic acid). The polymers 1 and 2 are built from 2D corrugated layer. The 2D layers are further interconnected to form the 3D framework by hydrogen bonds between water molecules and carboxyl groups. Both the complexes 1 and 2 exhibit efficient sensitized luminescence in the visible region in the solid state based on characterization emission of europium(III) and samarium(III) ions, respectively.

Two new 2D lanthanide–organic frameworks assembled by the asymmetric biphenyl-tetracarboxylic acid ligand have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. They display strong characteristic fluorescence from the f–f transitions of lanthanide ion, as well as high thermal stability.Figure optionsDownload as PowerPoint slide