Syntheses, structures and luminescence of lanthanide coordination polymers based on 5-(3-pyridylmethoxy)isophthalate ligand

Abstract

Eight new lanthanide coordination polymers, {[LnL(Bdc)0.5(H2O)2]·H2O}n [Ln=Ce(1), Pr(2), Nd(3), Sm(4), Eu(5), Gd(6), Tb(7), Dy(8)] (H2L=5-(3-pyridylmethoxy)isophthalic acid, H2Bdc=terephthalic acid), have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, PXRD and single crystal X-ray diffraction. Complexes 1–8 display isostructural 3D metal-organic frameworks (MOFs) constructed from 2D [LnL(H2O)2]n networks pillared by Bdc2− spacers. Tetradentate 5-(3-pyridylmethoxy)isophthalate ligand coordinates four Ln(III) ions via two bridging carboxyl groups. The 3D MOFs can be simplified as a (4,5)-connected tcs topological network with the Schläfli notation of {44.62}{44.66}. Thermal stabilities (TG-DSC) of these complexes are determined. Eu(5) and Tb(7) complexes emitting strong red and green luminescences demonstrate that the ligand-to-lanthanide energy transfer is efficient.