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The construction of metallosupramolecules is an interesting but challenging topic for chemists. Dedicated design of multidentate ligands is an effective approach for the construction of novel lanthanide supramolecules. Herein, we report on the stepwise design and syntheses of two flexible and multidentate ligands H2L1 and H4L2 based on the o‐vanillin. By regulating the coordination sites and mode of the ligands, two novel DyIII‐based supramolecules, [Dy4Na(μ2‐OH)2L14(H2O)5(CH3OH)](CF3SO3)3 ⋅ 3H2O ⋅ CH3OH (Dy4) and [Dy8L24(H2L2)4(H2O)4] ⋅ 4CH3OH ⋅ 12H2O (Dy8), have been obtained. Structural studies reveal that Dy4 and Dy8 show different nuclearity and topology: Dy4 shows a crescent‐like structure coordinated by the ligands in different coordination fashions in which two ligands chelate DyIII forming {Dy2} units and linked by the other two ligands; Dy8 is obtained from the supramolecular assembly, in which four completely deprotonated ligands construct the {Dy2} units and the units are linked by four di‐deprotonated ligands, forming a macrocycle topology. Additionally, magnetic measurements reveal that the two complexes exhibit slow magnetic relaxation behavior. [ABSTRACT FROM AUTHOR]

An unprecedented octanuclear dysprosium(iii) cluster with the formula [Dy8L6(μ3-OH)4(μ2-CH3O)2(CH3OH)6(H2O)2]·6H2O·10CH3OH·2CH3CN (1) based on a nonlinearly tritopic aroylhydrazone ligand H3L has been isolated, realizing the successful linking of pairwise interesting triangular Dy3 SMMs. It is noteworthy that two enantiomers (Λ and Δ configurations) individually behaving as a coordination-induced chirality presented in the Dy3 helicate are connected in the meso Dy8 cluster. Remarkably, alternating-current magnetic susceptibility measurements revealed that the Dy8 cluster shows typical SMM behavior inherited from its Dy3 helical precursor. It is one of the rare polynuclear Lnn SMMs (n ＞ 7) under zero dc field. [ABSTRACT FROM AUTHOR]

The reaction of the rigid polydentate Schiff-base H3L with different dysprosium carboxylates afforded two novel centrosymmetrical dinuclear DyIII compounds, [Dy2(HL)2-(CH3COO)2(DMF)2] (1) and [Dy2(HL)2(PhCOO)2(DMF)2]. 4DMF (2) with differing carboxylate groups. The two differing carboxylate groups affect the magnetic interaction and/or local anisotropy of the Dy ion, and therefore we have two compounds showing dissimilar magnetic behaviour. The acetato bridging groups with a syn-syn η1:η1:μ2 mode in compound 1 lead to the disappearance of slow magnetic relaxation under zero dc field. Nevertheless, typical SMM behaviour is observed for compound 2 with η2-chelating benzoate ligands. [ABSTRACT FROM AUTHOR]

A new Dy3 triangle bridged by a deprotonated alkoxyl group of a Schiff-base ligand together with a μ3-OH group has been prepared, in which intramolecular ferromagnetic interactions and single molecule magnet behaviour have been observed. [ABSTRACT FROM AUTHOR]

Two Dy compounds, [Dy4(μ4-O)L2(C6H5COO)6] ·3CH3OH ( 1) and [Dy2L(H2L)(teaH2)(o-vanillin)(H2O)](ClO4)2 ·2CH3OH ·H2O ( 2, teaH3 = triethanolamine), were assembled by the reactions of the salen-type ligand N, N′-bis(3-methoxysalicylidene)-1,2-cyclohexanediamine (H2L) and different dysprosium salts and bases. These compounds show both local chirality and slow magnetic relaxation. The former is induced by an unprecedented coordination mode of the ligand H2L, in which the N2O2 pocket encapsulates one Dy ion. Compound 1, which has four Dy ions in distinct coordination environments, demonstrates the rare Dy4 tetrahedron motif supported by a central μ4-O atom, which is akin to a chiral carbon atom in organic molecules, as revealed by single-crystal X-ray analyses. In contrast, the formation of 2, which shows an unusual structural motif with a tail, is driven by the presence of triethanolamine. In spite of the low-symmetry coordination geometry around each Dy ion, both compounds display slow magnetic relaxation behavior, but with fast quantum tunneling relaxation, as indicated by alternating current (ac) susceptibility measurements. [ABSTRACT FROM AUTHOR]

Abstract: Under hydrothermal conditions, Sm(NO3)3·6H2O reacts with N-(2-Hydroxyethyl)iminodiacetic acid (H3heidi), oxalic acid (H2Ox), in the presence of NiCl2·6H2O and NaOH, producing a novel two dimensional coordination polymer with the empirical formula of Na[Sm(Hheidi)(Ox)]·2H2O (1). X-ray diffraction analyses show that 1 crystallizes in the orthorhombic system, Pna21 space group, a =25.9008(19) Å, b =6.2593(5) Å, c =8.7624(6) Å, in which the network of SmNO8 and oxalate units forms an extended two dimensional layered structure. To the best of our knowledge, 1 represents the first structurally characterized lanthanide complex containing H3heidi ligand. The variable-temperature magnetic property of 1 has been investigated and the results of magnetic determination suggest the existence of a weak antiferromagnetic coupling between the samarium ions. [Copyright &y& Elsevier]

Two dinuclear triple-stranded helicates [Ln2L3]3+(Ln = Dy and Tb) obtained viaself-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 [Ln2L3]3+in the crystal. Each LnIIIion is coordinated by nine donor atoms in a distorted tricapped trigonal-prismatic arrangement. Alternating current (ac) susceptibility measurements of [Dy2L3]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 τ0of 10−7s. [ABSTRACT FROM AUTHOR]

The reaction of Dy(NO3)3·6H2O with the ligand 2-((1-hydroxybutan-2-ylimino)methyl)phenol (H2L, Scheme 1) generates the nonanuclear compound [Dy9L8(μ3-OH)8(μ4-OH)2(CH3OH)8](OH)(CH3OH)3(Dy9), whose single-crystal X-ray structure reveals the presence of two square pyramidal pentanuclear units assembled viathe apical metal center. The square pyramidal core of a previously reported [Dy5(μ4-OH)(μ3-OH)4(μ-η2-Ph2acac)4(η2-Ph2acac)6] (Dy5; Ph2acac = dibenzoylmethanide), is structurally related to those herein described; however, the magnetic properties of Dy9and Dy5are drastically different. Indeed, Dy5shows slow relaxation of magnetization while no out-of-phase ac signal is noticed for Dy9. The underlying mechanism is not clear due to the complexity of such systems; however, the different anisotropy of the respective structures, which is dictated by the combination of the metal topology, the ligands involved and the structural parameters of the molecule, is mostly responsible for the distinctive relaxation dynamics observed. [ABSTRACT FROM AUTHOR]

Abstract: Two new manganese complexes with multidentate 3-methoxysalicylaldehyde benzoylhydrazide ligand have been synthesized and structurally characterized. Variations of the reaction conditions (namely, the base, solvent or the counter ion) lead to drastic changes in the nature of the resulting coordination complexes. Depending on the anions involved a di- and a tetranuclear manganese structures are obtained. The magnetic properties of both complexes have been investigated, which show that the different complexes exhibit antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]

Abstract: A novel polymeric carboxylato-bridged praseodymium(III) complex of fumarate, [Pr2(fum)3(H2O)4]·5H2O (fum, fumarate dianion) has been synthesized and characterized by single-crystal X-ray diffraction studies, magnetic measurements and thermal studies. Single crystal X-ray structural determination reveals that it is a new porous three dimensional pillared layer framework with 1D channel for the accommodation of tetrameric water clusters. A preliminary treatment of the variable-temperature magnetic susceptibility using an expression including the ligand field effects and molecular field approximation leads to zJ′=−1.60cm−1, Δ =0.5cm−1 and g =0.84, suggesting the existence of a weak antiferromagnetic coupling between the praseodymium ions. [ABSTRACT FROM AUTHOR]

A novel dodecanuclear wheel with ten DyIIIions and two CoIIions bridged by four Schiff-base ligands and sixteen acetates represents the highest-nuclearity 3d–4f example of its type displaying single-molecule magnet behaviour. [ABSTRACT FROM AUTHOR]

Abstract: Three new tetranuclear nickel(II) complexes of general formula [Ni4(L)2(N3)2(CH3COO)2(CH3O)2]2·xCH3OH·yH2O (HL=HL1, HL2 and HL3; x =0, y =1 for 1; x =2, y =0 for 2 and x =2, y =4 for 3) were synthesized and characterized by single crystal X-ray diffraction and magnetic measurements. Single crystal X-ray studies reveal that all three complexes exhibit similar tetranuclear face-shared defective double-cubane structure, having azido-, alk/phenoxido- and acetato-bridges. Magnetic susceptibility measurements on the complexes in the range of 300–2K indicate ferromagnetic coupling between the metal ions. The slightly different magnetic behaviors observed are probably caused by subtle structural differences between the respective [Ni4O4N2] cores induced by ligand variation. [Copyright &y& Elsevier]