3D Heterometallic 3d–4f coordination polymers based on organodisulfonate ligand with isonicotinic acid as a co-ligand: synthesis, crystal structures, photoluminescent and magnetic properties

The hydrothermal reaction of rare earth nitrates, CuCN, 2,7-naphthalenedisulfonate (2,7-nds), and isonicotinic acid (Hina) affords a new family of 3D heterometallic 3d-4f coordination polymers, [Ln2Cu(2,7-nds)2(ina)4(H2O)4]·4H2O (Ln = Nd (1), Sm (2), Eu (3), Gd (4); 2,7-nds = 2,7-naphthalenedisulfonate, Hina = isonicotinic acid). Complexes 1-4 are structurally characterized by single crystal X-ray diffraction, elemental analysis (EA), FT-IR spectroscopy (IR), powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). X-Ray crystal structure analyses reveal that 1-4 are isomorphous with dinuclear subunit [Sm2(ina)4] binding Cu ions to generate 2D networks. Such 2D networks are pillared by linking 2,7-nds ligands to result in the 3D layer-pillared Ln(III)-Cu(II) coordination architectures. The valence of Cu salts changed in the reaction. In addition, the luminescence properties of 1-3 and the magnetic properties of 3 and 4 have also been investigated.