title: Terbium(III) and yttrium(III) complexes with pyridine-substituted nitronyl nitroxide radical and different β-diketonate ligands. Crystal structures and magnetic and luminescence properties.
abstract: A terbium(III) complex of nitronyl nitroxide free radical 2-(2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro1H-imidazolyl-1-oxy-3-oxide (NIT2Py), [Tb(acac)3NIT2Py]·0.5H2O (3) (acac = acetylacetonate), was synthesized for comparison with the previously reported [Tb(hfac)3NIT2Py]·0.5C7H16 (1) (hfac = hexafluoroacetylacetonate), together with their yttrium analogues [Y(hfac)3NIT2Py]·0.5C7H16 (2) and [Y(acac)3NIT2Py]·0.5H2O (4). The crystal structures show that in all complexes the nitronyl nitroxide radical acts as a chelating ligand. Magnetic studies show that 3 like 1 exhibits slow relaxation of magnetization at low temperature, suggesting single-molecule magnet behavior. The luminescence spectra show resolved vibronic structure with the main interval decreasing from 1600 cm(-1) to 1400 cm(-1) between 80 and 300 K. This effect is analyzed quantitatively using experimental Raman frequencies.
authors.affiliation: Laboratoire des Multimatériaux et Interfaces (UMR 5616), Université Claude Bernard Lyon 1 , Campus de la Doua, 69622, Villeurbanne Cedex, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Lannes
authors.forename: Mourad
authors.initials: M
authors.lastname: Intissar
authors.forename: Yan
authors.initials: Y
authors.lastname: Suffren
authors.forename: Christian
authors.initials: C
authors.lastname: Reber
authors.forename: Dominique
authors.initials: D
authors.lastname: Luneau