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ConspectusSingle-molecule magnets (SMMs) can retain their magnetization status preferentially after removal of the magnetic field below a certain temperature. The unique property, magnetic bistable status, enables the molecule-scale SMM to become the next-generation high-density information storage medium. SMMs’ new applications are also involved in high-speed quantum computation and molecular spintronics. The development of coordination chemistry, especially in transition metal (3d) and lanthanide (4f) complexes, diversifies SMMs by introducing new ones. In both 3d and 4f SMMs, the ligands play a fundamental role in determining the SMMs’ magnetic properties. The strategies for rationally designing and synthesizing high-performance SMMs require a comprehensive understanding of the effects of a crystal field.In this Account, we focus mainly on the magneto-structural correlations of 4f or 3d single-ion magnets (SIMs), within which there is only one spin carrier. These one-spin carrier complexes benefit from...

Nanocomposites containing soft and hard magnetic phases have attracted immense attention for energy-related and biomedical applications. With exchange coupling between nanoscale grains in the composites, magnetization of the soft magnetic phase can rotate coherently with that of the hard magnetic phase. In particular, good control of the soft and hard phases at the nanoscale in the composites is of great importance for effective exchange coupling, allowing us to make the best of the strengths of soft and hard magnetic phases and to optimize the magnetic properties for targeted applications. In this review, we present the recent progress in the chemical synthesis and applications of exchange-coupled nanocomposites. Firstly, the principle of nanomagnetism and exchange coupling is introduced. Secondly, the characterization of exchange-coupled nanocomposites is summarized. Thirdly, the chemical methods for the production of different exchange-coupled nanocomposites are presented. Finally, applications of exchange-coupled nanocomposites in magnetic energy storage and biomedicine are addressed.

Yellow (Himi)2 [(W(OH)2)2(Mn (H2O)3)2(Na3 (H2O)14)(BiW9O33)2] ·16H2O (I) (imi: imidazole) is synthesized by reaction of Na2WO4·2H2O, Bi(NO3)3·5H2O, imi, and MnCl2·6H2O (4.7:0.5:1:0.7 molar ratio) in water (stirring at 80 °C, 2 h; addn.

Framework-structured weak ferromagnets are new rising stars in molecule-based magnetic materials. The framework structures are powerful carriers for long-range ordering of spins. And weak ferromagnetism due to spin canting is an effective approach for magnets because of its frequent occurrence and desired spontaneous magnetization as long as the canting angle γ is large enough. In this critical review, we provide an overview of the various framework-structured weak ferromagnets based on different grades of ligands (from mono-atom to three-atom-like ligands). Particular emphasis is given to the relationships between structural features and the properties, rational employment of the ligands, and weak ferromagnetic strategies for molecule-based magnets with exciting properties and applications (273 references).

Compounds (II) and (III) are characterized by single crystal XRD, magnetic measurements, and DFT calculations.

The diverse magnetic properties of lanthanide-based magnetic molecular materials are introduced in the following organization. First, the general aspects of magnetic molecular materials and electronic states of lanthanide ions are introduced. Then the structures and magnetic properties are described and analyzed for molecules with one lanthanide ion, 4f-4f, 4f-3d and 4f-p magnetic coupling interactions. In each section, magnetic coupling, magnetic ordering and magnetic relaxation phenomenon are briefly reviewed using some examples. Finally, some possibilities of developing magnetic molecular materials containing lanthanide ions are discussed in the outlook part.

The DV-Xα-SCC method was used to study the electronic structure and chemical bonding of a series of rare earth metal clusters, R 7 X 12 Z. (R=Sc, Y, Pr; X=Cl; Z=Co, Fe, N) The results show that for the clusters containing a transition metal atom at the center, the number of cluster valence molecular orbitals (CVMOs) is 9; for the empty cluster and the clusters containing a nonmetal element, the number of CVMOs is 7, the same as in (B 6 H 6 ) 2

Synthesis of multifunctional magnetic nanoparticles (MFMNPs) is one of the most active research areas in advanced materials. MFMNPs that have magnetic properties and other functionalities have been demonstrated to show great promise as multimodality imaging probes. Their multifunctional surfaces also allow rational conjugations of biological and drug molecules, making it possible to achieve target-specific diagnostics and therapeutics. This review first outlines the synthesis of MNPs of metal oxides and alloys and then focuses on recent developments in the fabrication of MFMNPs of core/shell, dumbbell, and composite hybrid type. It also summarizes the general strategies applied for NP surface functionalization. The review further highlights some exciting examples of these MFMNPs for multimodality imaging and for target-specific drug/gene delivery applications.

A novel compound {[Fe(PZDA)(H2O)2]·2H2O}n has been synthesized and its structure determined by X-ray diffraction analysis, which consists of a quasi-ladder-like double chain running along a axis where Fe(II) ions are linked through the carboxylic groups acting as the edges of the ladder and pyrazine rings functioning as the rungs. Variable-temperature magnetic susceptibility study indicates the presence of spin frustration in the double chain compound.

Reaction of Ln(ClO4)3 (Ln=Nd or Gd) with L-serine at pH 6.0 yielded the aqua hexanuclear clusters [Nd6(μ6-O)(μ3-OH)8(H2O)24](ClO4)8·6 H2O (1) and [Gd6(μ6-O)(μ3-OH)8(H2O)24](ClO4)8·6 H2O (2). They are isomorphous and comprised of a regular octahedron of 6 lanthanide ions encapsulating a μ6-O2− anion and capped by a μ3-OH group on each face. The structure can also be regarded as an oxo-centered octahedron embedded in a cube formed by 8 μ3-OH groups.

[Gd(DMF)2(H2O)3Cr(CN)6]·H2O is the first lanthanide−transition metal array with a flat two-dimensional brick-wall-like molecular structure. The antiferromagnetic coupling between the adjacent Gd−Cr...

The design, synthesis, and structural and magnetic properties of the two new bimetallic complexes [Sm(DMF)4(H2O)2Cr(CN)6]·H2O and [Sm(DMF)2(H2O)3Cr(CN)6]·H2O (DMF = N,N-dimethylformamide) are presented. [Sm(DMF)4(H2O)2Cr(CN)6]·H2O was prepared by the reaction between Sm3+ and [Cr(CN)6]3- in a methanol−DMF solution, while [Sm(DMF)2(H2O)3Cr(CN)6]·H2O was prepared by the reaction between Sm3+, DMF, and [Cr(CN)6]3- in the molar ratio of 1:2:1 in H2O. [Sm(DMF)4(H2O)2Cr(CN)6]·H2O crystallizes in the monoclinic space group of P2(1)/c with a = 13.161(3) A, b = 12.928(3) A, c = 19.174(4) A, β = 109.82(3)°, and Z = 4, while [Sm(DMF)2(H2O)3Cr(CN)6]·H2O is in the triclinic space group P1 with a = 7.7535(1) A, b = 9.4307(3) A, c = 16.2905(5) A, α = 94.1590(14)°, β = 100.0597(18)°, γ = 100.9154(18)°, and Z = 2. The structure of [Sm(DMF)4(H2O)2Cr(CN)6]·H2O possesses a cyano-bridged one-dimensional (1D) zigzag chain structure with alternating Sm(DMF)4(H2O)2 and Cr(CN)6 moieties. [Sm(DMF)2(H2O)3Cr(CN)6]·H2O consists of c...

A novel molecular-based magnet of three-dimensional (3-D) cyanide-bridged bimetallic assembly, {[Cu(en)2]3[W(CN)8]2·H2O}∞ (1), where en = ethylenediamine, was synthesized and structurally characterized. The assembly has a three-dimensional network structure extended by three kinds of CuII–NC–WV–CN–CuII linkages with very long axial Cu–Ncyanide interactions due to Jahn–Teller effects. The network is based on a W8Cu12 cube-like unit with eight [W(CN)8]3− anions at the corners of the distorted cube and twelve [Cu(en)2]2+ cations at the middle of the edges, in which a coordination anion [W(CN)8]3− acting as template/guest is capsulated in the cavity of the W8Cu12 cube. Magnetic studies reveal that the complex displays 3-D ferromagnetic ordering over the lattice below the Curie temperature at around 2 K.

A facile and selective route based on a precipitate slow-release controlled process was developed to produce both high-quality MnSe2 and α-MnSe uniform microcrystals in aqueous solution at low temperatures (100−180 °C). The magnetic properties of the two samples were investigated in detail. This synthetic method will have potential applications in material science, especially in fabricating diluted magnetic semiconductors. These uniform microcrystals might be useful in microdevices, seed crystals, and magnetic cells.

Heterometallic 3d−4f complexes are of high interest in molecular magnetism: the lanthanide ions bring large and, in most cases, anisotropic magnetic moments. The combination of 3d and 4f metal ions, which differ through their chemistries and stereochemical preferences, leads to a rich variety of heterometal complexes, ranging from discrete entities to 3-D coordination polymers. This paper reviews recent achievements in this field: (i) oligonuclear complexes for studying the nature of the 3d−4f exchange interaction; (ii) construction of single-molecule magnets; (iii) magnetic properties of 3d−4f coordination polymers.

We present here the first examples of Cu-azide compounds synthesized by using protonated diamine ions as cationic templates: (dmenH(2))[Cu(6)(N(3))(14)] and (trimenH(2))[Cu(6)(N(3))(14)](dmenH(2)(2+): N,N'-dimethylethylenediammonium; trimenH(2)(2+): N,N,N'-trimethylethylenediammonium). Both compounds possess a similar, rarely observed anionic Cu-azide layer, which consists of [Cu(6)(N(3))(14)(2-)](n) anionic chains linked by asymmetric end-to-end azido bridges. The chain, in turn, is made up of elongated Cu(6) rings, with double and single end-on azido linkages between the square-planar Cu(2+) sites within the ring and double end-on azido bridges serially connecting the rings. The molecular geometry results in ferromagnetic interactions within the Cu-azide layer in both compounds. The interlayer separations are determined by the cations, with the shortest interlayer CuCu separations being 8.016 A for the dmenH(2)(2+) compound and 9.106 A for the trimenH(2)(2+) compound. These different interlayer separations tune the magnetic properties of the two materials. The dmenH(2)(2+) compound displays long-range antiferromagnetic ordering at low temperature and short-range ferromagnetic interaction at high temperature, while only short-range ferromagnetism was observed in the trimenH(2)(2+) compound at 2-300 K.

The combination of some three-atom bridges with paramagnetic 3d transition metal ions results in the systematic isolation of molecular magnetic materials, ranging from single-molecule and single-chain magnets to layered weak ferromagnets and three-dimensional porous magnets. The design strategy and role of secondary components, such as co-ligands, templates and other mixed short ligands are discussed.

Using hydrazine (N2H4) as a cobridge with azide, a honeycomb-layered cobalt(II) coordination polymer, Co(N2H4)(N3)2 (1), is obtained that exhibits spin-canted weak ferromagnetism with TN of 13.5 K.

A new complex (1) of Prussian blue analogue with the composition of K0.2Mn1.4Cr(CN)6·6H2O was prepared and characterized structurally as well as magnetically. The crystal structure of complex 1 was...

Two novel 3d−5d Cu(II)−W(V) cyano-bridged compounds, [Cu(tn)]3[W(CN)8]2·3H2O (1) and [Cu(pn)]3[W(CN)8]2·3H2O (2), where tn is 1,3-diaminopropane and pn is 1,2-diaminopropane, have been synthesized and characterized structurally and magnetically. The X-ray analyses of the two complexes reveal that they exhibit two-dimensional layer structures with the following crystal data: space group P21/c, a = 24.459(5) A, b = 9.6426(19) A, c = 18.037(4) A, β = 90.45(3)°, V = 4253.9(15) A3, Z = 4 for 1; and space group P21/c, a = 24.126(5) A, b = 9.8889(19) A, c = 18.077(3) A, β = 90.204(4)°, V = 4312.9(14) A3, and Z = 4 for 2. Magnetic properties of the two compounds have also been investigated. Both show typical metamagnetic behavior. The critical field at which the interlayer antiferromagnetic ground-state switches to a ferromagnetic state is ∼1.25 T for 1 and 0.35 T for 2 at 1.8 K.

Nanosized LaCoO3 cobaltite oxide powder with perovskite structure was successfully synthesized at a relatively low calcination temperature using an amorphous heteronuclear complex, LaCo(DTPA)·6H2O, as a precursor. The precursor decomposed completely into cobaltite oxide above 400 °C according to the DTA and TGA results. XPS revealed that the decomposed species was composed of LaCoO3 cobaltite oxide after the precursor was calcined at 500 °C for 2 hours. XRD demonstrated that nanosized LaCoO3 crystalline powder with perovskite structure was formed after the calcination temperature increased to 600 °C. The grain size and the crystal size of LaCoO3 increased with the calcination temperature from 500 °C to 800 °C, and the heat-treatment time has a less obvious effect on the grain size and the crystal size. It is a useful way to synthesize nanosized perovskite oxides using an amorphous complex as a precursor. This method can be easily quantitatively controlled.

Various 3'-azido, 3'-amino, 2',3'-unsaturated, 2',3'-dideoxy, and 5-substituted analogues of pyrimidine deoxyribonucleosides have been prepared and tested against Moloney-murine leukemia virus (M-MULV), a mammalian T-lymphotropic retrovirus in vitro. Among these compounds, the 3'-azido analogues of thymidine, 2'-deoxy-5-bromouridine, and 2'-deoxy-5-iodouridine, the 2',3'-unsaturated analogue of thymidine and and 2'-deoxycytidine, and 2',3'-dideoxycytidine were found to be most active, with ED50 values of 0.02, 1.5, 3.0, 2.5, 3.7, and 4.0 microM, respectively. These active compounds were nontoxic to the host SC-1 cells up to 100 microM concentration. The 3'-azido analogues of thymidine and 2'-deoxy-5-bromouridine were also tested in vitro against HTLV-III/LAV/AAV ("AIDS" virus) and found to be significantly active, with ED50 values of 0.23 and 2.3 microM, respectively. The structure-activity relationships are discussed.