title: A new family of Ln-radical chains (Ln = Nd, Sm, Gd, Tb and Dy): synthesis, structure, and magnetic properties.
abstract: Five new one-dimensional rare earth-nitronyl nitroxide radical complexes [Ln(hfac)3(NIT-3BrPhOMe)]n (Ln = Nd (1), Sm (2), Gd (3), Tb (4), Dy (5); hfac = hexafluoroacetylacetonate; NIT-3BrPhOMe = 2-(3'-bromo-4'-methoxyl)-4,4,5,5-tetramethyl-imidazolyl-1-oxyl-3-oxide) have been successfully prepared and structurally characterized. Five complexes possess linear chain structure in which the NIT-3BrPhOMe radical ligands link Ln(hfac)3 units through the oxygen atoms of nitronyl nitroxide groups. DC magnetic studies show that Nd, Sm and Gd complexes are paramagnetic above 2.0 K, whereas Tb and Dy complexes show antiferromagnetic ordering with T(N) = 19.9 K and 6.4 K, respectively. Moreover, Tb and Dy complexes exhibit frequency-dependence of ac magnetic susceptibilities, suggesting the presence of slow magnetic relaxation. This work demonstrated that the substituents of the nitronyl nitroxide radical and the lanthanide ion can play a crucial role in modulating the magnetic behavior for one-dimensional lanthanide-radical systems.
authors.affiliation: Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry and Tianjin Key Laboratory of Metal and Molecule-based Material Chemistry, Nankai University, Tianjin 300071, China. llicun@nankai.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Hu
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Wang
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.forename: Qinglun
authors.initials: Q
authors.lastname: Wang
authors.forename: Licun
authors.initials: L
authors.lastname: Li
authors.forename: Daizheng
authors.initials: D
authors.lastname: Liao