Linear trinuclear mixed-metal CoII-GdIII-Co II single-molecule magnet: [L2Co2Gd][NO 3]·2CHCl3 (LH3 = (S)P[N(Me)N=CH-C 6H3-2-OH-3-OMe]3)

10.1021/ic070321cInorganic Chemistry46135140-5142INOC

Tridecanuclear [MnIII 5 LnIII 8 ] Complexes Derived from N-tButyl-diethanolamine: Synthesis, Structures, and Magnetic Properties

The synthesis, structures and magnetic properties of a family of heterometallic [MnIII 5 LnIII 8 (μ3-OH)12(L2)4(piv)12- (NO3)4(OAc)4]- (Ln = Pr, 2; Nd, 3; Sm, 4; Gd, 5; Tb, 6) aggregates are reported. The complexes were obtained from the direct reaction of N-tbutyldiethanolamine (H2L2) with Mn(OAc)2 3 4H2O and Ln(NO3)3 3 6H2O in the presence of pivalic acid (pivH) in MeCN under ambient conditions. Compounds 2-6 are isomorphous and crystallize in the monoclinic space group P21/n with four molecules in the unit cell. The complexes have a centrosymmetric tridecanuclear anionic core consisting of two distorted inner heterometallic [MnIIILnIII 3 (μ3-OH)4]8+ cubane subunits sharing a common Mn vertex flanked by four edge-sharing heterometallic [MnIIILnIII 2 (μ3-OH)4]5+ defect cubane units. Complexes 2-6 are the first high-nuclearity 3d-4f aggregates reported to date using tBu-deaH2 as ligand. These compounds show no evidence of slow relaxation behavior above 1.8 K, which appears to be the consequence of the very weak or non-existent magnetic interactions between the MnIII and LnIII ions resulting from the particular angles at the bridging oxygens

Family of MnIII 2Ln2(μ4-O) Compounds: Syntheses, Structures, and Magnetic Properties

An isostructural family of tetranuclear aggregates [MnIII 2Ln2(O)(Piv)2(hep)4(NO3)4] 3 MeCN (where Ln = YIII (1), PrIII (2), NdIII (3), GdIII (4), TbIII (5), DyIII (6), HoIII (7), and YbIII (8)) is reported. They were obtained from the reactions of 2-(2-hydroxyethyl)pyridine (hepH) with a preformed hexanuclear manganese complex, [Mn6], and the respective lanthanide salt. The complexes are isomorphous and represent a new heterometallic 3d-4f complex type for this class of ligand. The structural core of 1-8 consists of a distorted Mn2Ln2 tetrahedron with the four metal centers linking through a μ4-O2- bridging atom. The magnetic properties of all complexes were investigated by variable temperature magnetic susceptibility and magnetization measurements. The magnetic data of all compounds suggest that antiferromagnetic interactions are present between adjacent paramagnetic centers. Complexes 5-7 containing highly anisotropic lanthanide ions (Tb, Dy, and Ho) show slow relaxation of their magnetization