A Novel Layered Neodymium Squarate MOF Intercalating Free Ammonium and Squarate Ions {(NH4)2[Nd2(H2O)10(C4O4)3]C4O4}n: Synthesis, Crystal Structure and Thermal Decomposition

The X-ray study of the title compound {(NH4)(2)[Nd-2(H2O)(10)(C4O4)(3)]C4O4}(n)(1) reveals that it crystallizes in the monoclinic system, space group P2(1)/c (N degrees: 14), with unit cell parameters, a=7.483(3), b=27.866(7), c=6.766(2) angstrom and =103.95(3)degrees. The crystal structure consists of a Nd-MOF/salt alternating layers, where neodymium-metal organic framework (Nd-MOF) layer lies in (200) plane, formed by isolated [NdO9] polyhedra linked by bridging squarate ligands in mu(2)- and mu(4)-coordination modes. The salt layers lie at x=0 and are sandwiched between Nd-MOF layers; they consist of squarate anions and ammonium cations (in 1:2 ratio). Hydrogen bonds and - stacking play a pivotal role in structure cohesion between Nd-MOF layers leading to the formation of a 3D networks. The features of the IR spectrum are consistent with the crystal structure. The TG-DTA reveals that first water is lost from the coordination compound, and then the anionic ligands along with ammonium cations are removed leaving metal oxide as residue of the substance.