Synthesis, Structure and Magnetic Properties of a Linear Trinuclear Mn(II) Complex with a Multifunctional Group Ligand

By use of a new ligand containing both salicylic acid moiety and salicylaldehyde Schiff base moiety, 5-（2-hydroxybenzylideneamino）-2-hydroxybenzoic acid （H3L）, a linear trinuclear Mn（II） complex was prepared. This complex crystallizes in triclinic, space group P1 with a = 12.0196（7）, b = 13.7440（13）, c = 15.7554（14） , α = 111.529（3）, β = 96.691（2）, γ = 94.802（2）o, C96H100Mn3N6O32, Mr = 2014.64, V = 2382.0（3） 3, Z = 1, μ = 0.478, Dc = 1.404 g/cm3, F（000） = 1049, R = 0.0554 and wR = 0.1610 for 8973 observed reflections （I 〉 2σ（I））. The complex consists of a trinuclear cluster and two solvate ethanol molecules. Three linearly disposed Mn atoms, with an inversion center on the central one, are bridged by six carboxylate groups from six bulky mono-anionic ligands （H2L-）, and the octahedral coordination spheres for each of the metal centers are thus formed, with the aid of additional ligation of two small molecules （ethanol and water） to both ends. The magnetic properties of the title complex are also included in this paper.

Electronic structure and magnetic properties of substitutional transition-metal atoms in GaN nanotubes

The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6-16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Co- doped GaN NTs induce the largest local moment of 4#B among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it.

EFFECTS OF Sn AND Sb ON STRUCTURE AND MAGNETIC PROPERTIES OF HIGH INDUCTION ORIENTED SILICON STEEL

Effects of Sn and Sb on the structure and magnetic properties of high induction oriented silicon steel have been investigated.The heats with Sn or Sb possess rather fine primary and secondary gram sizes.Sn or Sb promotes the finer AlN particles,increases the amount of pre- cipitated AlN after normalizing and strengthens the ability of inhibition.After decarburizing annealing,the texture components of{110}〈115〉and〈110〉〈001〉tend to increase and form more secondary grain nuclei.

Crystal Structure and Magnetic Properties of a Dinuclear Terbium Compound Tb_2(μ_2-anthc)_4(anthc)_2(1,10-phen)_2

A dinuclear Tb（Ⅲ） compound, Tb_2（μ_2-anthc）_4（anthc）_2（1,10-phen）_2（1, Hanthc = 9-anthracenecarboxylic acid and 1,10-phen = 1,10-phenanthroline）, was synthesized under solvothermal condition and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P1, with a = 12.5061（12）, b = 13.3168（10）, c = 15.0079（12） ？, α = 110.620（7）, β = 102.941（7）, γ = 107.036（7）o, V = 2081.8（3） ？~3, Z = 1, C_（114）H_（70）N_4O_（12）Tb_2, M_r = 2005.58, D_c = 1.600 g/cm^3, μ = 1.759 mm^（-1）, F（000） = 1008, the final R = 0.0294 and w R = 0.0608 for 8900 observed reflections with I 〉 2s（I）. In compound 1, two Tb（Ⅲ） ions are linked by four carboxylate groups of the bridging anthc– ligands to give a dinuclear Tb_2（μ_2-anthc）_4 unit wherein each Tb（III） ion is further capped by a terminal anthc– ligand and a 1,10-phen ligand in a chelating fashion. Detailed direct-current and alternating-current susceptibility measurements showed no slow magnetism relaxation phenomenon was observed for 1.

Synthesis, Structure and Magnetic Properties of a 3D Interpentrating Network Based on 4-Imidazol-1-yl-benzoic Acid and Azide Ligands

A new CoⅡ coordination complex, namely [Co（iba）（N3）]n, was prepared by the hydrothermal reaction of Co（NO3）2·6H2O with Na N3 in the presence of 4-imidazol-1-yl-benzoic acid（Hiba）. Compound 1 crystallizes in orthorhombic, space group Pbca with a = 6.782（2）, b = 19.93（5）, c = 15.96（4） A, V = 2157.2（3） A3, Z = 8, C10H7O2N5 Co, Mr = 228.14, Dc = 1.774 g/cm^3, F（000） = 1160, μ（Mo Kα） = 1.592 mm-1. The final R and w R are 0.0706 and 0.1990 for 1160 observed reflections with I 2σ（I）. Each iba- coordinates in a bidentate fashion with two CoⅡ ions and every two adjacent CoⅡ ions were connected by one azido ion to form a 3D two-fold interpenetrating framework. Thermogravimeteric analysis（TGA） of compound 1 reveals that the loss of moiety of azido ion occurs from 200 oC to about 260 oC and the framework begins to decompose above 300 oC. The magnetic property investigation of compound 1 demonstrates that it displays ferromagnetic coupling between CoⅡ ions.

Synthesis, Crystal Structure and Magnetic Properties of a New Zn(II)-Nitronyl Nitroxide Complex

A new complex [Zn（NIT-1′-MeBzlm）Cl2（H2O）] （NIT-1′-MeBzlm = 2-{2′-[（1′- methyl）benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been prepared and structurally characterized by X-ray diffraction method. Crystal data： monoclinic, space group P21/n, Z = 4, C15H21Cl2N4O3Zn, Mr = 441.63, a = 7.2225（10）, b = 30.849（4）, c = 8.8758（13）A, β = 103.904（2）°, V = 1919.6（5）A^3, Dc = 1.528 g/cm^3, μ（MoKα） = 1.579 mm^-1, F（000） = 908, R = 0.0436 and wR = 0.1029 for 2456 observed reflections with I〉 2σ（I）. X-ray analysis reveals that the Zn（Ⅱ） ion is four-coordinated with a distorted tetrahedron. There also exist H-bonds, π-π piling interactions and weak intermolecular contacts between the NO groups which form a mutual stagger 3-D network configuration. Magnetic investigation reveals that there exists intermolecular antiferro- and ferromagnetic interactions in the title complex.

Synthesis, Crystal Structure and Magnetic Properties of a One-dimensional Loop-like Iron(Ⅱ) Complex:[Fe(Haip)_2(H_2O)_2]_n (Haip = 5-Ammoniumisophthalato)

An iron（Ⅱ） coordination polymer, [Fe（Haip）2（H2O）2]n （1, Haip = 5-ammoniumiso- phthalato）, has been hydro/solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectrum and magnetic measurement. Compound 1 crystalizes in monoclinic, space group P2/c with a = 6.9874（14）, b = 9.960（2）, c = 12.894（4） A, β = 117.47（2）°, Fe（C8H6NO4）2（H2O）2, Mr = 452.16, V= 796.2（3） A3, Z = 2, Dc = 1.886 g.cm-3, p = 1.017 mm-1, F（000） = 464.0, 2.71〈0〈28.42°, R = 0.0307, wR = 0.0840 and S = 1.005. Single-crystal X-ray diffraction analysis reveals that 1 features an infinite one-dimensional loop-like chain structure and Haip ligand in 1 is of zwitterionic form. Magnetic measurement results show the dominated ferromagnetic interactions among Fe11 atoms.

Crystal Structure and Magnetic Properties of a Two-dimensional Compound{(Me2NH2)4[Co(SIP)2]·2(DMF)·3(H2O)}n

A new cobalt（II） compound, {（Me2NH2）4[Co（SIP）2]·2（DMF）·3（H2O）}n（1, H3 SIP =5-sulfoisophthalic acid）, has been synthesized under solvothermal condition and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal system,space group P 4 21 m, with a = 14.3080（7）, b = 14.3080（7）, c = 12.1837（9） ?, V = 2494.2（3） ?~3, Z =2, CHNOSCo, Mr = 929.87, Dc = 1.238 g/cm, μ = 0.496 mm, F（000） = 982, flack parameter of 0.007（9）, the final R = 0.0767 and wR = 0.2110 for 2391 observed reflections with I >2σ（I）. The tetrahedral Co（II） ions are linked by carboxylate groups of the 5-sulfoisophthalate ligands to form an anionic two-dimensional（2D） layer displaying a（4,4） square network, which was charge-balanced by the [MeNH] + cations occupying the spaces between the 2D layers. Magnetic properties of 1 have been investigated in detail using direct-current and alternating-current susceptibility measurements.

Synthesis, Crystal Structure and Magnetic Properties of a Cobalt(Ⅱ) Complex with Quinoxaline-substituted Nitronyl Nitroxide Radicals

A new complex with the formula [Co（acac）_2（NITQ）_2]×2CH_2Cl_2 1（acac = acetylacetone, NITQ = 2-（2′-quinoxalinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide）, was synthesized and elucidated structurally as well as magnetically in detail. The crystal belongs to the monoclinic system, space group P2_1/c with a = 9.6896（1）, b = 20.539（4）, c = 12.147（2） ？, β = 93.84（3）°, M_r = 997.65, V = 2412.1（8） ？~3, Z = 2, Dc = 1.374 g/cm, F（000） = 1038, m = 0.635 mm^（-1）, the final R = 0.0539 and w R = 0.1289 for 5998 observed reflections（I 〉 2σ（I））. The Co（Ⅱ） ion is coordinated by two nitrogen atoms of quinoxaline rings from two NITQs and four oxygen atoms from two acac ions to complete a distorted octahedral coordination environment. Compound 1 is further linked into a three-dimensional（3D） supramolecular network by hydrogen-bonding, Cl×××O weak contact and π···π stacking interactions. The magnetic measurements show compound 1 exhibits weak ferromagnetic interactions.

Effect of Dy on Structure and Magnetic Properties of CoPt Alloys

The effects of Dy on the microstructure and magnetic properties of DyxCo50-xPt50 alloys were investigated. The XRD results indicate that all the alloys homogenized at 1000 ℃ contain only a single A 1 （fcc） phase, while the alloys annealed at 675℃ consist of a hard-magnetic face-eentered-tetragonal （fct） phase and a magnetically soft face-centered-cube （fcc） phase. Maximum values for the coercivity and remanence ratio mr were achieved in DY0.4Co49.6Pt50 alloys annealed at 675 ℃ for 80 min. For the series of Dy Co50-xPt50 alloys annealed at 675 ℃ for 60 min, H decreases monotonically with increasing Dy concentration, but mr is first enhanced and then weakened,

Influence of Substitution of Transition Elements for Fe on the Structure and Magnetic Properties of the Nd_(16)Fe_(75)AI_2B_7 AHoy

1.IntroductionThe influence of substitution of variouselements for Fe on the magnetic propertiesof the NdFeBalloy has been investi-gated by several authors,among which theAl substitution can increase the coercivity[1]and the addition of both Co and Al has beenproved to have a positive effect on im-proving both the coercivity and other per-

Electronic Structure and Magnetic Properties of Rh_(13) Cluster with Three Possible Symmetries

Electronic and magnetic properties of 13-atom Rh clusters with three possible high symmetry geometries have been studied by using the first-principles DV-LSD method. An anomalous symmetry dependence of the cluster magnetism was found that the total magnetic moment of the icosahedral Rh13 cluster is smaller than that of the other two lower-symmetry clusters in a wide range of interatomic spacings. An energy difference is identified to explain this anomalous relationship, which has been found to be also useful for judging whether the broadening technique is correctly used and whether multiple input potentials must be used to reach the actual ground state in the LSD calculations. The calculated results are compared and discussed with those of previous theory and recent experiment. The actual geometry of the Rh13 cluster is suggested to be a distorted icosahedron.

Crystal structure and magnetic properties of Nd(Mn_(1-x)Fe_x)_2Si_2 compounds

X-ray powder diffraction, resistivity and magnetization studies have been performed on polycrystalline Nd（FexMn1-x）2Si2 （0≤x 〈 1） compounds which crystallize in a ThCr2Si2-type structure with the space group 14/mmm. The field-cooled temperature dependence of the magnetization curves shows that, at low temperatures, NdFe2Si2 is antiferromagnetic, while the other compounds show ferromagnetic behaviour. The substitution of Fe for Mn leads to a decrease in lattice parameters a, c and unit-cell volume V. The Curie temperature of the compounds first increases, reaches a maximum around x=0.7, then decreases with Fe content. However, the saturation magnetization decreases monotonically with increasing Fe content. This Fe concentration dependent magnetization of Nd（FexMn1-x）2Si2 compounds can be well explained by taking into account the complex effect on magnetic properties due to the substitution of Mn by Fe. The temperature＇s square dependence on electrical resistivity indicates that the curve of Nd（Fe0.6Mn0.4）2Si2 has a quasi-linear character above its Curie temperature, which is typical of simple metals.

Synthesis,Crystal Structure and Magnetic Properties of a Coordination Polymer [Ni(C_(10)H_(13)NO_4)(H_2O)_2]_n

A novel organic polycarboxylate N-cyclohexylaziridines-2R,3S-dicarboxylic acid was synthesized and reacted with Ni2（OH）2CO3.As a result,a coordination polymer was obtained.It crystallizes in orthorhombic,space group Pbca with a = 8.6325（10）,b = 10.5414（13）,c = 27.644（3） ,Z = 4,V = 2515.5（5） 3,C20H34N2Ni2O12,Mr = 611.91,Dc = 1.616 g/cm3,μ = 1.562 mm-1,F（000） = 1280,the final R = 0.0320 and wR = 0.0677 for 2854 independent reflections with Rint = 0.0390.Crystal structure shows that the coordination environment around the Ni（Ⅱ） ion can be described as a slightly distorted octahedron.The ligands act as a bridge through the carboxyl O atoms and join the Ni atoms into an infinite 1D chain structure.The 1D chain forms a 2D network through intermolecular O-H…O hydrogen bonds.The magnetic susceptibility measurements（2～300 K） agree with a weak antiferronmagnetic interaction between neighboring Ni ions in the chain.

Synthesis, Crystal Structure and Magnetic Properties of Cobalt(II) Complex Involving Imino Nitroxide Radicals

A novel compound [Co(IM2-Py)2(NO3)]?(NO3) (IM2-Py = 2-(2?-pyridyl)-4,4,5,5- tetramethylimidazoline-1-oxyl) has been prepared and structurally characterized by X-ray diffrac- tion method. It crystallizes in orthorhombic, space group P212121 with a = 11.031(2), b = 13.492(3), c = 20.467(4) ?, V = 3046.0(11) ?3, C24H32CoN8O8, Mr = 619.51, Z = 4, Dc = 1.351 g/cm3, μ(MoKα) = 0.620 mm?1, F(000) = 1292, R = 0.0506 and wR = 0.0845 for 3752 observed reflections with I > 2σ(I). X-ray analysis reveals that the crystal structure consists of [Co(IM2- Py)2(NO3)]+ moiety and a NO3 anion. The cobalt(II) ion is six-coordinated with a distorted octahedral geometry. Tempera- ? ture dependence of susceptibility measurements show that there exist an antiferromagnetic inter- action in the compound.

Synthesis, Crystal Structure and Magnetic Properties of Heptanuclear Manganese Complexes with Schiff-base Ligand

One new mixed-valence heptanuclear manganese complex, [Mn^ⅡMn^Ⅲ6O2L6-(NaCH3COO)2(CH3COO)4](1)(L = 3-ethoxy-6-((2-hydroxyethyl)imino)methyl) phenol, was synthesized by treating the Schiff-base ligand with Mn(acac)3·4H2O and characterized by elemental analysis, IR spectra, thermogravimetric analyses and X-ray single-crystal diffraction. 1 has a similar new mixed-valence heptanuclear structure. The magnetic measurements indicate that 1 exhibits the antiferromagnetic interactions.

Dependence of Structure and Magnetic Properties on Annealing Temperature in Fe(72.5)Cu1Nb2V2Si(13.5)B9 Alloy

The magnetic properties of Fe_(72.5)Cu_1Nb_2V_2Si_(13.5)B_9 alloy are investigated from an amorphous to a nanocrystalline and complete crystalline state. The sample annealed at 550℃ for 0.5 h shows a homogeneous nanocrystalline structure and presents excellent soft magnetic properties. When the specimens were annealed at a temperature above 600℃, the magnetic properties are obviously deteriorated because the grain size grows up, exceeding the exchange length.

Synthesis,Crystal Structure and Magnetic Properties of a Co(Ⅱ) Complex Containing 2′-(l′-Methyl)benzimidazolyl-substituted Nitronyl Nitroxide

A new complex [Co（NIT-1′-MeBzIm）2Cl2]（NIT-1′-MeBzIm = 2-{2′-[（l′-methyl）-benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been prepared and structurally characterized by X-ray diffraction method.The complex crystallizes in the monoclinic system,space group C2/c,Z = 4.Crystal data：C30H38Cl2CoN8O4,Mr = 704.51,a = 17.074（3）,b = 21.350（3）,c = 11.6962（19）,β = 108.879（2）°,V = 4034.3（11）3,Dc = 1.160 g/cm3,μ（MoKα） = 0.597 mm-1,F（000） = 1468,R = 0.0422 and wR = 0.1141 for 2577 observed reflections with I 2σ（I）.X-ray analysis reveals that the Co（Ⅱ） ion is six-coordinated with a distorted octahedral geometry.Temperature dependence of susceptibility measurements shows the existence of antiferromagnetic interactions between the Co（Ⅱ） ion and the radicals（J =-52.88 cm-1）.

Hydrothermal Synthesis, Crystal Structure and Magnetic Properties of a Novel Zero-dimensional Manganese(Ⅱ) Complex with 2,2′-Diphenic Acid and 1,10-Phenanthroline Ligands

A novel metal-organic coordination polymer [Mn3（2,2′-dipha）3（phen）6]n·3nH2O （2,2′-dipha = 2,2′-diphenic acid, phen = 1,10-phenanthroline） 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, and magnetic susceptibility measurements. The crystal crystallizes in triclinic, space group P1 with a = 16.921（5）, b = 18.307（5）, c = 18.450（5）A , α = 113.369（5）, β = 108.529（5）, γ = 102.984（5）°, V = 4553（2）A^ 3, C114H72Mn3N12O14.25, Mr = 2002.66, Dc = 1.461 g/cm^3, μ（MoKα） = 0.488 mm^-1, the final F（000） = 2058, Z = 2, R = 0.0491 and wR = 0.0980 for 9087 observed reflections （I 〉 2σ（I））. In the crystal structure, the manganese atom is six-coordinated with two carboxylate oxygen atoms from different carboxylate groups of the same dipha and four nitrogen atoms from two different phen ligands, showing a slightly distorted octahedral geometry. Fur- thermore, it exhibits a zero-dimensional structure with dipha-Mn-phen- as building units. Variable- temperature magnetic measure shows an overall anti-ferromagnetic behavior for compound 1.

Composition Dependence of Structure and Magnetic Properties in Manganese Doped Nanocrystalline ZnO Particles Prepared by Co-Precipitation

Mn-doped nanocrystalline ZnO particles have been successfully synthesized at low temperature (80?C) by the coprecipitation method using zinc sulfatehepta hydrate and NaOH. The structural and magnetic properties have been characterized using X-ray diffraction (XRD), Energy dispersive x-ray, vibrating sample magnetometer and electron spin resonance. XRD measurements revealed that the sample posses hexagonal wurzite structure. From the Rietveld refined XRD spectra, the lattice parameters, average crystallite size and microstrain values was obtained. In this range of doping concentrations all samples show an expansion of the lattice parameters relative to the bulk samples. From magnetic measurements we observed the presence of room temperature ferromagnetic order in our Mn-doped ZnO samples.