Interplane distances modulation in lanthanide-based coordination polymers

We present here two new materials, Er-2(BDC)(3)(H2O)(6) (1) and Er-2(NDC)(3)(H2O)(6) (2), where BDC stands for 1,4-benzenedicarboxylate and NDC stands for 2,6-naphthalenedicarboxylate ligand. In addition to their compositions, both structures adopt the same general arrangement: that is, a succession, along the (c) over right arrow -axis, of erbium atoms planes and organic spacers-ligands planes. The longer naphthalene derivative ligand increases the c parameter, but the organization inside the erbium cations planes is kept, including the nature and the geometry of the coordination spheres of the lanthanide ions, the number and the repartition of the water molecules, and the network of hydrogen bonding. The chemical nature, the flexibility, and the topology of the organic ligands allow the preservation of the organic-inorganic interface within the materials. This study clearly shows the opportunity to imagine new lanthanide-based materials with the tools of crystal engineering.