Syntheses, structural characterization and luminescent properties of M2(ATPA)3(DMF)2(H2O)2 (M = Nd, Sm, Eu, Gd, Tb, Dy; ATPA = 2-aminoterephthalate, DMF = N,N-dimethylformamide)

Six isomorphous metal–organic frameworks: M2(ATPA)3(DMF)2(H2O)2 (M = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6); ATPA = 2-aminoterephthalate, DMF = N,N-dimethylformamide), were synthesized by the self-assembly of lanthanide ions, 2-aminoterephthalate, DMF and H2O. Their crystal structures determined by X-ray crystallography reveal interpenetrating frameworks. Compounds 2, 3, 5 and 6 exhibit mainly ligand luminescence at room temperature while 3 exhibits enhanced Eu3+ emissions at 77 K. Magnetic studies indicate 4 is paramagnetic with slight Gd3+–Gd3+ couplings.