title: Lanthanide complexes of tritopic bis(hydrazone) ligands: single-molecule magnet behavior in a linear Dy(III)3 complex.
abstract: Tritopic pyridinebis(hydrazone)-based ligands typically produce square M(9) [3 × 3] grid complexes with first-row transition-metal ions (e.g., M = Mn, Fe, Co, Cu, Zn), but with larger lanthanide ions, such coordination motifs are not produced, and instead linear trinuclear complexes appear to be a preferred option. The reaction of 2pomp [derived from pyridine-2,6-bis(hydrazone) and 2-acetylpyridine] with La(III), Gd(III), and Dy(III) salts produces helical linear trinuclear [Ln(3)(2pomp)(2)]-based complexes, where each metal ion occupies one of the three tridentate ligand pockets. Two ligands encompass the three metal ions, and internal connections between metal ions occur through μ-O(hydrazone) bridges. Coligands include benzoate, nitrate, and N,N-dimethylformamide. The linear Dy(III)(3) complex exhibits single-molecule magnet behavior, demonstrated through alternating-current susceptibility measurements. Slow thermal magnetic relaxation was detected in an external field of 1800 Oe, where quantum-tunneling effects were suppressed (U(eff) = 14 K).
authors.affiliation: Department of Chemistry, Memorial University, St. John's, Newfoundland A1B 3X7, Canada.
authors.forename: Muhammad U
authors.initials: MU
authors.lastname: Anwar
authors.forename: Santokh S
authors.initials: SS
authors.lastname: Tandon
authors.forename: Louise N
authors.initials: LN
authors.lastname: Dawe
authors.forename: Fatemah
authors.initials: F
authors.lastname: Habib
authors.forename: Muralee
authors.initials: M
authors.lastname: Murugesu
authors.forename: Laurence K
authors.initials: LK
authors.lastname: Thompson