Four lanthanide-carboxylate coordination polymers with mixed 2,3-naphthalenedicarboxylate and phen ligands: syntheses, structures, luminescent and magnetic properties

Four new lanthanide-carboxylate coordination polymers of the formula [Ln3L4(phen)4(H2O)4](ClO4)·2H2O, (Ln = Dy (1), Tb (2), Ho (3) and Er (4), L = 2,3-naphthalenedicarboxylate and phen = 1,10-phenanthroline) were solvothermally synthesized. Their structures as well as magnetic and photoluminescent properties were completely investigated. Complexes 1-4 are isostructural and exhibit 1D ribbon-like chains with envelope-like sixteen-membered rings. The DyIII and TbIII complexes show the corresponding characteristic luminescence in the visible region and the ErIII complex shows luminescence in the near-infrared region upon excitation with UV rays. Studies on the magnetic properties are reported. The Dy(III) analog complex 1 exhibits slow magnetic relaxation and could be a new example of a Dy(III) SMM (single molecule magnet)