3D lanthanide metal-organic frameworks constructed from 2,6-naphthalenedicarboxylate ligand: synthesis, structure, luminescence and dye adsorption

Abstract

A series of novel isostructural 3D lanthanide metal-organic frameworks {[Ln2(NDC)3(H2O)4]·(DMF)4}n (Ln=Eu(1), Gd(2), Tb(3), Er(4), Yb(5), Dy(6), Y(7), Lu(8), H2NDC =2,6-Naphthalenedicarboxylic acid, DMF=N,N-dimethylformamide) with a rhombic channel along the b axis and high thermal stabilities, have been successfully synthesized under solvothermal conditions. The network can be described as 2, 4, 5-connected net with Schäfli symbol of (42.62.82)2(42.63.85)2(6). Luminescent studies illustrate that 1, 2, 7 and 8 exhibit strong luminescent emitting of the corresponding Ln(III) centers in the visible range, while 5 shows near-infrared range (NIR) luminescence. Further studies of 1 and 2A (activated product of 2) show that 1 displays good stability in different solvents and excellent fluorescence sensing for organic solvent small molecules and 2A ([Gd2(NDC)3(H2O)4]n) exhibits good adsorption capacity for organic dyes in water, especially for crystal violet.