A series of new microporous lanthanide frameworks [Ln(C8H3NO6)(L)0.5(H2O)]·3H2O (Ln=Pr, Nd, Sm and Gd, and L=C8H4O4 or C8H4O4/C8H3NO6): Syntheses, characterization and photoluminescence properties

Crystal structures and gas adsorption behavior of new lanthanide-benzene-1,4-dicarboxylate frameworks

“…The colors of the crystals are in good agreement with the characteristic colors of the corresponding lanthanide ions. The crystals showed a tint of yellow color which is consistent with the presence of the nitrated BDC 2-(NO2-BDC 2-) derived in situ under strong acidic hydrothermal conditions [23,24]. The existence of NO2-BDC 2is confirmed by characteristic υ(C-N) and υ(N-O) in the IR spectra of all complexes (see Appendix).…”

“…1). The unit cell parameters of 2-5 are in good agreement with those of [Ln(NO2-BDC)(L)0.5(H2O)]•3H2O (Ln = Pr, Nd, Sm and Gd; L = BDC 2-or BDC 2-/NO2-BDC 2-) [23], with a descending tendency across the series attributed to the lanthanide contraction. The asymmetric units of 2-5 are similar comprising only one unique lanthanide metal ion which exhibits the same nine-fold coordination of the squareface capped square antiprismatic geometry, SAPRS-{LaO9}, as exemplified in Fig.…”

“…Similar site disorder is also observed in the structures of 3 and 5 which are isostructural to 2 and 4. The disorder in structures 2 and 4 is however more complicated and similar to those observed in [Ln(NO2-BDC)(L)0.5(H2O)]•3H2O (Ln = Pr, Nd, Sm and Gd, and L = BDC 2or BDC 2-/NO2-BDC 2-) [23]. In addition to site disorder at the nitro group of one of the NO2-BDC 2ligands, there are two types of crystallographic disorder, including site and substitutional disorder, at the nitro group of the other ligand.…”

“…Following our interest in extending the use of lanthanide ions in fabricating new microporous frameworks [23], six new complexes have been synthesized. The colors of the crystals are in good agreement with the characteristic colors of the corresponding lanthanide ions.…”

“…The framework includes the one-dimensional rectangular channel extending in the same direction as the {Eu(μ3-OCO)4(μ2-OCO)2( 1 , 1 -OCO)(OH2)} chains, housing the unbound water molecules. In the same fashion to [Ln(NO2-BDC)(L)0.5(H2O)]•3H2O [23], these unbound water molecules are organized as the edge-shared pentagons by strong hydrogen bonding interactions (Table 2). Besides the hydrogen bonding interactions, there are - interactions between the adjacent organic ligands.…”