title: Observation of slow magnetic relaxation in triple-stranded lanthanide helicates.
abstract: Two dinuclear triple-stranded helicates [Ln(2)L(3)](3+) (Ln = Dy and Tb) obtained via self-assembly from the ligand HL (2,6-diformyl-4-methylphenol di(benzoylhydrazone)) and lanthanide perchlorate have been synthesized and characterized. The crystal structural analysis demonstrates that three ligand strands wrap around a pseudo-threefold axis defined by the two metal ions, leading to a 'meso'-relation between the right- (Δ) and left-hand (Λ) configurations of [Ln(2)L(3)](3+) in the crystal. Each Ln(III) ion is coordinated by nine donor atoms in a distorted tricapped trigonal-prismatic arrangement. Alternating current (ac) susceptibility measurements of [Dy(2)L(3)](3+) reveal a frequency-dependent out-of-phase signal under a 700 Oe dc field, indicating the onset of the slow relaxation of magnetization with a roughly estimated activation energy of ∼5 K and τ(0) of 10(-7) s.
authors: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
authors: Shuang-Yan
authors: SY
authors: Lin
authors: Gong-Feng
authors: GF
authors: Xu
authors: Lang
authors: L
authors: Zhao
authors: Yun-Nan
authors: YN
authors: Guo
authors: Yang
authors: Y
authors: Guo
authors: Jinkui
authors: J
authors: Tang
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry*; D003408:Cresols / Q000737:chemistry*; D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D010472:Perchlorates / Q000737:chemistry*
chemical_list: C474508:2,6-diformyl-4-methylphenol; D001547:Benzaldehydes; D003408:Cresols; D028581:Lanthanoid Series Elements; D008024:Ligands; D010472:Perchlorates; C494474:perchlorate