One-dimensional Salen-type Chain-like lanthanide(III) coordination polymers: Syntheses, crystal structures, and fluorescence properties

Article abstract of DOI:10.1002/zaac.201000366

Four salen-type lanthanide(III) coordination polymers [LnH ₂L(NO₃)₃(MeOH)_x]_n [Ln = La (1), Ce (2), Sm (3), Gd (4)] were prepared by reaction of Ln(NO ₃)₃·6H₂O with H₂L [H ₂L = N,Na-bis(salicylidene)-1,2-cyclohexanediamine]. Single-crystal X-ray diffraction analysis revealed that H₂L effectively functions as a bridging ligand forming a series of 1D chain-like polymers. The solid-state fluorescence spectra of polymers 1 and 2 emit single ligand-centered green fluorescence, whereas 3 exhibits typical red fluorescence of Sm^III ions. The lowest triplet level of ligand H₂L was calculated on the basis of the phosphorescence spectrum of Gd^III complex 4. The energy transfer mechanisms in the lanthanide polymers were described and discussed.