The syntheses, structures, magnetic and luminescent properties of five new lanthanide(III) complexes based on tetrazole 1-acetic ligand

Five new lanthanide complexes based on tetrazole-l-acetic ligand and 2,2'-bipyridine as auxiliary ligand have been solvothermally synthesized with the formulas [Ln(2)(1-tza)(2)(NO3)(4)(2,2'-bipy)(2)] [Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5), 1-tza = tetrazole 1-acetic and 2,2'-bipy = 2,2'-bipyridine] and structurally characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. The single-crystal X-ray diffraction data reveal that complexes 1-5 are dinuclear structures constructed by nitrate-O-bridged and mu(1,3) carboxyl groups from 1-tza ligand, in which each nine-coordinated center Ln(III) ion is in a slightly distorted capped square antiprism geometry. The magnetic behaviors of 1-5 have been investigated. The solid-state photoluminescent measurements illustrate that complexes Eu 3 and Tb 4 display the strong fluorescent emissions in the visible region, whereas Nd 1 shows the characteristic near-infrared(NIR) luminescence. In addition, thermogravimetric analysis of Eu 3 is also described.