Lanthanide coordination polymers constructed by a new semirigid bridging salicylamide ligand: Synthesis, structure and luminescence properties

• We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand.
• All the lanthanide coordination polymers form 1D annular chain.
• The SmIII, EuIII and TbIII complex exhibit characteristic luminescence.

A new semirigid exo-bidentate ligand incorporating thenylsalicylamide terminal groups, namely 1,4-bis{[(2′-thenylaminoformyl)phenoxyl]methyl}-2,5-bismethylbenzene was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. All the lanthanide coordination polymers exhibit the same metal-to-ligand molar ratio of 2:3 and the semirigid exo-bidentate ligand as a bridging ligand, reacts with lanthanide nitrates forming 1D annular chains {[Ln2(NO3)6L3]∞ (Ln = Nd (1), Sm (2), Eu (3), Tb (4)}. The samarium, europium and terbium containing compounds exhibit luminescence of the referring trivalent lanthanide ions, giving an orange luminescence for SmIII, a red luminescence for EuIII and a green luminescence for TbIII triggered by an efficient antenna effect of the thenylsalicylamide group.

We presented here a new semirigid bridging exobidentate ligands with terminal thenylsalicylamide groups, which resulted in the formation of 1D annular lanthanide coordination polymers with interesting supramolecular structures. Luminescence studies demonstrated that the tetrapodal salicylamide ligand exhibits a good antenna effect with respect to the Eu(III) and Tb(III) ion.Figure optionsDownload as PowerPoint slide