Assembly, crystal structures and luminescent properties of the lanthanide nitrate coordination polymers with 1,5-bis{[(2′-(2-picolylaminoformyl))phenoxyl]methyl}naphthalene

A new amide type bridging ligand, 1,5-bis{[(2′-(2-picolylaminoformyl))phenoxyl]methyl}naphthalene (L), and its complexes with lanthanide ions (Ln═Sm, Eu, Gd, Tb, and Dy) have been designed and assembled. The crystal structures of {[EuL(NO3)3(CH3OH)](H2O)}n and [TbL(NO3)3(CH3OH)]n display one-dimensional (1-D) zig-zag coordination polymeric chains. At the same time, the solid state luminescent properties of the Sm, Eu, Tb, and Dy complexes were investigated at room temperature. The complexes all exhibit characteristic luminescence emissions of the central metal ions under UV light excitation. The lowest triplet state energy level (T1) of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Tb(III) ion than other lanthanide ions.

Graphical AbstractA series of luminescent one-dimensional zig-zag coordination polymers have been rationally assembled by the reaction of lanthanide nitrate and a new amide type bridging ligand 1,5-bis{[(2′-(2-picolylaminoformyl))phenoxyl]methyl}naphthalene.Figure optionsDownload as PowerPoint slideResearch Highlights
► A new amide type bridging lignd L and its lanthanide complexes were synthesized.
► The crystals of {[EuL(NO3)3(CH3OH)](H2O)}n and [TbL(NO3)3(CH3OH)]n were obtained.
► One-dimensional zig-zag lanthanide coordination polymers were designed and assembled.
► The complexes exhibited characteristic luminescence emissions of lanthanide ions.
► The fluorescence quantum yield of the Tb(III) complex is the strongest.