title: Trinuclear [CoIII 2 -LnIII] (Ln=Tb, Dy) single-ion magnets with mixed 6-chloro-2-hydroxypyridine and Schiff base ligands.
abstract: The Schiff base ligand N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H(2)valdien) and the co-ligand 6-chloro-2-hydroxypyridine (Hchp) were used to construct two 3d-4f heterometallic single-ion magnets [Co(2) Dy(valdien)2 (OCH(3))(2) (chp)(2)]⋅ClO(4)⋅5 H(2)O 1 and [Co(2) Tb(valdien)(2) (OCH(3))(2)(chp)(2)]⋅ClO(4)⋅(2) H(2)O⋅CH(3)OH(2). The two trinuclear [Co(III) 2 Ln(III)] complexes behave as a mononuclear Ln(III) magnetic system because of the presence of two diamagnetic cobalt(III) ions. Complex 1 has a molecular symmetry center, and it crystallizes in the C2/c space group, whereas complex 2 shows a lower molecular symmetry and crystallizes in the P(2)1/c space group. Magnetic investigations indicated that both complexes are field-induced single-ion magnets, and the Co(III)(2)-Dy(III) complex possesses a larger energy barrier [74.1(4.2) K] than the Co(III)(2) -Tb(III) complex [32.3(2.6) K].
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Institution of Chemistry, Chinese Academy of Sciences, Center for Molecular Sciences, Beijing 100190 (P.R. China), Fax: (+86) 010-62569349. cmliu@iccas.ac.cn.
authors.forename: Cai-Ming
authors.initials: CM
authors.lastname: Liu
authors.forename: De-Qing
authors.initials: DQ
authors.lastname: Zhang
authors.forename: Xiang
authors.initials: X
authors.lastname: Hao
authors.forename: Dao-Ben
authors.initials: DB
authors.lastname: Zhu
keywords: cluster compounds; cobalt; lanthanides; magnetic relaxation; single-ion magnets