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A new FeIII6cluster, [Fe3L2(ida)(μ-OH)3(μ-O)]2·4ClO4·2CH3OH·8H2O (1) (where L = N-methyl-N,N-bis(2-pyridylmethyl)amine; H2ida = iminodiacetic acid), has been synthesized and magnetic properties are shown. The asymmetric unit of 1contains a triangular [Fe3L2(ida)(μ-OH)3(μ-O)]2+unit and two such trinuclear units are further connected by two ida2−, generating a hexanuclear FeIIIcore in 1. Variable temperature magnetic susceptibility studies reveal the presence of dominant antiferromagnetic exchange interactions and the variable-field and temperature magnetization measurements establish that each Fe3cluster has S= 5/2 ground state and the coupling between the two moieties is almost zero. [ABSTRACT FROM AUTHOR]

Seven isomorphous 1D chain Ln3+complexes Ln(BTA)(HCOO)(H2O)3(Ln = Pr (1), Gd (2), Eu (3), Tb (4) Dy (5), Er (6) and Yb (7)), and two formate coordinating and bridging 3D Ln3+complexes Ln(HCOO)3(Ln = Pr (8) and Nd (9)) have been synthesized and characterized by single crystal X-ray diffraction analysis. Although the Ln3+ions in 1–7have different radius, the trivalent lanthanide ions in 1–7show the same coordinated environment. The well-defined single crystal structures of 8and 9are first samples for formate-bridged Ln3+metallic complexes. The luminescent properties of solid samples of 2–5at room temperature and the magnetic property of 2have been also reported and discussed in this paper. [ABSTRACT FROM AUTHOR]

A new compound [Cu(NITPhCH 3 ) 2 Cl 2 ] (NITPhCH 3 2-(4-methyl-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) has been characterized spectroscopically. A crystal structure analysis has shown the copper ion to be planar, coordinated by two chlorine atoms and two oxygen (nitroxyl) atoms. Based on magnetic susceptibility measurements the compound was found to exhibit a moderately strong antiferromagnetic interaction (J=-107.44 cm -1 ) between copper(II) and the radical. [ABSTRACT FROM AUTHOR]

Investigates the synthesis and magnetic properties of cyano-bridged bimetallic 4f-3d arrays with one-dimensional chain and two-dimensional brick wall molecular structures. Performance of single-crystal X-ray and magnetic susceptibility measurements; Incorporation of organic ligands; Use of dimethylformamide as a ligand.

Examines the magnetic characteristics of the cyano-bridged two dimensional honeycomb-like bimetallic assemblies. Existence of a short-range ferromagnetic interaction of the complexes; Exhibition of long-range magnetic ordering above room temperature; Performance of a single-crystal structure analysis.

A magnetic MOF with two distinct functions was prepared and characterized: [2 + 2] photodimerization and antiferromagnetism with a well-pronounced anion-tunable spin–flop transition below 2.5 K were both observed. [ABSTRACT FROM AUTHOR]

Nanomagnetism is the origin of many unique properties in magnetic nanomaterials that can be used as building blocks in information technology, spintronics, and biomedicine. Progresses in nanomagnetic principles, distinct magnetic nanostructures, and the biomedical applications of nanomagnetism are summarized. [ABSTRACT FROM AUTHOR]

Two novel three-dimensional complexes formulated as [M3(bime)2(μ3-OH)2(HO-BDC)2]n (M = Co, 1; Cu, 2) [bime = 1,2-bis(imidazol-1′-yl)ethane, HO-H2BDC = 5-hydroxyisophthalic acid] have been hydrothermally synthesized and characterized. Both 1 and 2 exhibit similar structural frameworks resulting from one-dimensional metal/oxygen chains extended by HO-BDC, but the bridging modes of HO-BDC and coordination environments of metal centers are different. Complexes 1 and 2 crystallize in the orthorhombic system, space group Pbcn, a = 18.458(2) [18.2119(12) for 2] Å, b = 12.0616(14) [11.6847(7)] Å, c = 11.4859(14) [12.0688(6)] Å, and Z = 4 (4). Magnetic studies show that 1 displays a slow magnetic relaxation, a large hysteresis, and distinct finite-size effects and 2 contains an antiferromagnetic chain. [ABSTRACT FROM AUTHOR]

By employing hydrothermal method, six transition metal sulfates containing hydrazine (N2H4) have been obtained: [M(SO4)2(N2H5)2]n (M = Mn(1), Co(2), Ni(3)) and [M(N2H4)SO4]n (M = Mn(4), Co(5), Ni(6)). Their crystal structures and magnetic properties have been investigated experimentally and theoretically. Compounds 1-3 consist of one-dimensional sulfate bridged homometallic chains with protonated hydrazine molecule as terminal ligand, and compounds 4-6 are hydrazing-sulfate mixed bridged homometallic three-dimensional frameworks. Compounds 1-6 exhibit antiferromagnetic coupling between M2+ ions, but their magnetic properties differ at low temperatures because of the different single-ion anisotropy and crystal structures. The magnetostructural correlations and the magnetic coupling mechanism are analyzed by density functional theory calculations (DFT). [ABSTRACT FROM AUTHOR]

Two coordination polymers, Ni(endi)(N3)2 (endi = 1,2-bis(tetrazol-1-yl)ethane) (1) and Ni(4-acpy)2(N3)2 (4-acpy = 4-acetylpyridine) (2), are obtained by employing a couple of cobalt complex as referances. Both compounds have similar 2D (4,4) EE azide-nickel layer structures, but different interlayer separations. Their EE azide bridges are vigorously twisted, with the torsion angle τ value 88.3° and 107.6° for 1 and 89.2 for 2. Different from most EE azide compounds, ferromagnetism is distinctly present, ordering below Tc = 25 K for 1 and Tc = 23 K for 2. Fitting of magnetic susceptibility data using the spin Hamiltonian H = —2JΣS1S2 gives the ferromagnetic intralayer coupling J = 14.70(6) cm-1 for 1 and 14.32(0) cm-1 for 2, respectively. The magnetostructural correlations of 1 have been calculated using the density function theory based method. The computational results are consistent with the trend of the experimental data. One possible mechanism was proposed to explain the emergence of ferromagnetism based on the theoretical studies, and the ferromagnet construction approach was also proposed accordingly. [ABSTRACT FROM AUTHOR]

The use of alkyl ammonium cations resulted in four compounds of (A)[FeIII(ox)Cl2] (A = Et3NH+ (1a, 1b), Me4N+ (2), and n-Bu4N+ (3); ox = oxalate), whose structures and magnetic properties were characterized. In all cases, the metal Fe(III) ions are six-coordinated by four oxygen atoms from two bischelating oxalate ligands and the two terminal Cl- ions in the cis position. Thus they form similar anionic 1D [FeIII(ox)Cl2]- chains. The chains are separated by alkyl ammonium cations in the lattice, and the cation size seems to control the interchain separation and packing patterns in the solid. A parallel arrangement of the [FeIII(ox)Cl2]- chains is observed for la, 2, and 3, while a crossed one is observed for 1b, which is a polymorph of 1a. Magnetic studies reveal the antiferromagnetic intrachain interactions in all compounds. The last three compounds, 1b, 2, and 3, show spin canting below 14.5, 9.5, and 3.8 K, respectively. The dipolar interaction over the interchain distance is proposed to be the result of 3D magnetic ordering in the materials. [ABSTRACT FROM AUTHOR]

A series of cyano-bridged LnIIIRuIII2 coordination polymers, Ph4P{Ln(NO3)2[Ru(acac)2(CN)2]2} [Ln = Tb (1), Dy (2), Er (3), Gd (4); Hacac = acetylacetone] have been synthesized by the reaction of Ln(NO3)3 with trans-Ph4P[Ru- (acac)2(CN)2] in methanol. X-ray crystallographic determination reveals that these compounds are isostructural and have a wavy (4,4) layer structure with the Ln3+ ions bridged by trans-[Ru(acac)2(CN)2]. Magnetic studies shows that the magnetic coupling between the Ln(lll) and Ru(III) ions through the cyano bridges in 1-4 is negligibly weak. [ABSTRACT FROM AUTHOR]

The preparation and crystal structures of five cyano-bridged Fe-Mn complexes, [(bipy)2FeII(CN)2MnII(bipy)2]2(CIO4)4 (1), [(bipy)2FeII(CN)2MnII(DMF)3(H2O)]2(CIO4)4 (2), {[(Tp)FeIII(CN)3]2MnII(DMF)2(H2O)}2 (3), {[(Tp)FeIII(CN)3]2MnII- (DMF)2}n (4), and Na2[MnIIFeII(CN)6] (5) (bipy = 2,2′-bipyridine, Tp = tris(pyrazolyl)hydroborate), are reported here. Compounds 1–4 contain the basic Fe2(CN)4Mn2 square building units, of which 1-3 show the motif of discrete molecular squares of Fe2(CN)4Mn2 and 4 possesses a 1D double-zigzag chainlike structure, while compound 5 is a 3D cubic framework analogous to that of Prussian blue. Compounds 1 and 2 show weak ferromagnetic interactions between two Mn(II) ions through the bent -NC-Fe(II)-CN-bridges. Compound 3 shows weak antiferromagnetic coupling between the Fe(III) and Mn(II) ions, while compound 4 displays a metamagnetic-like behavior with TN = 5.2 K and Hc = 10.5 kOe. Compound 5 exhibits a ferromagnetic ordering with Tc = 3.5 K, coercive field, Hc, = 330 G, and a remnant magnetization of 503 cm³ Oe mol-1. [ABSTRACT FROM AUTHOR]

The synthesis, X-ray data, and electronic structures of two manganese(lll) 1D polymers ligated by tetrachlorocatechol, [Mn2lll(H2L¹)(Cl4Cat)4·2H2O]∞ (1) and [Mn2lll(H2L²)(Cl4Cat)4·2CH3CN·2H2O]∞ (2), are reported. The electronic structures of the complexes have been determined by UV-vis-near-IR, IR, electron paramagnetic resonance (EPR), and magnetic susceptibility measurements. Both 1 and 2 are air stable in the solid state and in solution, unlike most of the previously reported o-quinone-chelated transition-metal complexes, Electronic spectroscopy exhibits a strong near-IR band near 1900 nm for both, suggesting the presence of a mixed-valence semiquinone-catecholate oxidation state of the catechol ligands, Mn2lll(Cl4Cat)2(Cl4SQ)2, together with the pure catecholate forms. The presence of this isomer was further supported by EPR and magnetic susceptibility measurements. The complexes undergo intramolecular electron transfer (valence tautomerism) upon an increase of the temperature involving the equilibrium Mn2lll(Cl4Cat)2(Cl4SQ)2 ⇌ Mn2ll(Cl4SQ)4. This phenomenon is reversible and is studied in solution using UV-vis-near-IR spectroscopy. [ABSTRACT FROM AUTHOR]

Investigates the crystal structures and magnetic properties of bimetallic Ni polymers. Two-dimensional grid-like layers of the polymers; Metamagnetic behavior the complex; Intralayer ferromagnetic and interlayer antiferromagnetic interactions; Presence of long-range antiferromagnetic ordering.