A Novel Binuclear Cu(Ⅱ) Complex with Nitroxide Radicals Exhibiting Ferromagnetic Interactions

A new binuclear Cu（Ⅱ） complex with nitronyl nitroxide radicals [Cu（NIT3Py）2Cl2]2（NIT3Py = 2-（3＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in monoclinic,space group C2/c with a = 38.483（4）,b = 7.2450（8）,c = 27.559（3） ,β = 134.0180（10）°,V = 5525.6（10） 3,C48H64Cl4Cu2N12O8,Mr = 1206.00,Z = 4,Dc = 1.450 g/cm3,μ（MoKα） = 1.025 mm-1,F（000） = 2504,S = 1.066,the final R = 0.0471 and wR = 0.1121 for 3286 observed reflections（I 2σ（I））.The title complex consists of centrosymmetric dinuclear units [Cu（NIT3Py）2Cl2]2,in which the copper ions are square-pyramidally coordinated by two pyridyl nitrogen atoms of two radical ligands and three chlorine anions,two of which bridge the copper ions.The magnetic measurements show ferromagnetic interactions between the copper ions and the radical ligands.

Synthesis and ferromagnetic interaction in oxamido- bridged heterodinuclear copper (Ⅱ)- chromium (Ⅲ) complexes

Four μ-oxamido heterodinuclear complexes, [Cu(oxae)Cr(L)2] (NO3)3,where oxae denotes the N, N’-bis (2-aminoethyl) oxamido dianion and L represents 1, 10-phenanthroline ( phen); 5-nitro-1, 10-phenanthroline (NO2-phen); 5-methyl-1, 10-phenanthroline (Me-phen) and 2,2’-bipyridine (bpy), have been synthesized and characterized by elemental analyses, magnetic moments (at room temperature) and molar conductivity measurements and spectroscopy. It is proposed that these complexes have extended oxamido-bridged structures consisting of a copper (Ⅱ) ion and a chromium (Ⅲ) ion, which have a square planar environment and octahedral environment, respectively. The cryomagnetic properties of the [Cu(oxae)Cr(bpy)2] (NO3)3(1) and [Cu(oxae)Cr(phen)2] (NO3)3(2) complexes have been measured over the range of 4.2-300 K. The least-squares fit of the experimental data based on the spin Hamiltonian, H = - 2JS1·S2, the exchange integrals (J) were evaluated as + 36.9 cm-1 for 1 and +35.8 cm-1 for 2. The results have confirmed

A Diphenoxo-bridged Ferromagnetic Copper(Ⅱ) Dimer Based on N-(2-Hydroxybenzyl)salicylaldimine

A new dinuclear copper（Ⅱ） complex, [Cu（L）（py）]2 1 （H2L = N-（2-hydroxybenzyl）- salicylaldimine, py = pyridine）, has been synthesized and characterized by elemental analysis, IR and UV spectra. 1 crystallizes in space group P2 1/n with a = 8.2106, b = 10.715, c = 17.864A, β = 99.365°, V = 1550.7A3, Z = 4, C19H16CuN2O2, Mr = 367.88, Dc = 1.576 g/cm3,μ（MoKα） = 1.422 mm-1, F（000） = 756, the final R = 0.0280 and wR = 0.0746. Complex 1 is a centrosymmetric dimer with two copper（H） centers, two py ligands and two L2- ligands. Each L2- ligand donates its azomethine nitrogen and one of the phenolate groups to one copper（Ⅱ） ion and shares the other phenolate group between the two copper（H） ions, affording a Cu2O2 plane. Each copper（Ⅱ） center has a slightly distorted square pyramidal geometry with a bridging phenolate group at the apex. Magnetic studies suggest the presence of a weak ferromagnetic interaction Via two phenoxo bridges. The magnetic susceptibility data （2-300 K） of complex 1 were analyzed by means of H = -2JS1S2 -DSz. The least-squares fitting of the data to the theoretical equation leads to J = 10.3 cm-1, g = 2.03, D = 0.67 cm-1 and R = ∑（Xobsd -Xcalcd）2/∑Xobsd2= 2.76 × 10^-3.

Synthesis,Crystal Structure and Ferromagnetic Properties of a New Dicyanamide Bridged Dicopper(Ⅱ) Complex with IM-1′-MeBzIm-κ2 N,O Mode

A new dinuclear copper（Ⅱ） complex with imino nitroxide radicals [Cu2（NO3）2（IM- 1 ′-MeBzIm）2（dca）2] （IM-1 ′-MeBzIm = 2-{2′-[（1′-methyl）benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl, dca = dicyanamide anion） has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in triclinic, space group P 1^-, with α = 9.440（5）, b = 10.124（6）, c = 11.603（7） A, α = 102.904（7）, β = 94.033（6）,γ = 104.299（7）°, C34H40Cu2N16O8, Mr = 927.90, V= 1038.2（10） A^3, Z = 1, Dc = 1.484 g/cm^3, μ（MoKα） = 1.093 mm^-1, F（000） = 478, R = 0.0609 and wR = 0.1512 for 2889 observed reflections with Ⅰ 〉 2σ（I）. X-ray analysis reveals that two Cu（Ⅱ） atoms are bridged by two dicyanamides to form a centrosymmetric Cu（Ⅱ）-Cu（Ⅱ） dinuclear entity. Every Cu（Ⅱ） ion is five-coordinated with a distorted square pyramidal coordination geometry and IM-1′-MeBzlm ligand coordinates to the metal ion with the k^2 N（1 ′-MeBzlm）, O（IM） mode to avoid steric hindrance with the methyl group in the complex. Meanwhile, the molecules are linked by intermolecular hydrogen bonds, leading to a 1-D chain structure. Moreover, such chains are further linked by π-π stacking interactions to form a 2-D network structure. Magnetic measurement demonstrates that the intramolecular exchange couplings between Cu（Ⅱ） ion and the IM-1 ′-MeBzIm are ferromagnetic with J = 12.46 cm^-1, where the spin Hamitonian is defined as H^ = -2JS^1S^2 within the complex.

Spin transfer torque in the semiconductor/ferromagnetic structure in the presence of Rashba effect

Spin transfer torque in magnetic structure occurs when the transverse component of the spin current that flows from the nonmagnetic medium to ferromagnetic medium is absorbed by the interface. In this paper, considering the Rashba effect on the semiconductor region, we discuss the spin transfer torque in semiconductor/ferromagnetic structure and obtain the components of spin-current density for two models：（i） single electron and（ii） the distribution of electrons. We show that no matter whether the difference in Fermi surface between semiconductor and Fermi spheres for the up and down spins in ferromagnetic increases, the transmission probability decreases. The obtained results for the values used in this article illustrate that Rashba effect increases the difference in Fermi sphere between semiconductor and Fermi sphere for the up and down spins in ferromagnetic. The results also show that the Rashba effect, brings an additional contribution to the components of spin transfer torque, which does not exist in the absence of the Rashba interaction. Moreover, the Rashba term has also different effects on the transverse components of the spin torque transfer.

(Ba_(1−x)Na_(x))F(Zn_(1−x)Mn_(x))Sb: A novel fluoride-antimonide magnetic semiconductor with decoupled charge and spin doping

We report the successful synthesis and characterization of a novel 1111-type magnetic semiconductor(Ba_(1−x)Na_(x))F(Zn_(1−x)Mn_(x))Sb(0.05≤x≤0.175)with tetragonal ZrSiCuAs-type structure,which is isostructural to the layered iron-based superconductor La(O,F)FeAs.Na substitutions for Ba and Mn substitutions for Zn introduce carriers and local magnetic moments,respectively.Ferromagnetic interaction is formed when Na and Mn are codoped,demonstrating that local magnetic moments are mediated by carriers.Iso-thermal magnetization shows that the coercive field is as large as-12000 Oe,which is also reflected in the large split between the temperature-dependent magnetization in zero-field-cooling and field-cooling condition.AC susceptibility under zero field demonstrates that samples evolve into spin-glass state below spin freezing temperature T_(f).The measurements of temperature-dependent resistivity indicate that(Ba_(1−x)Na_(x))F(Zn_(1−x)Mn_(x))Sb exhibits semiconducting behaviour.

Synthesis, Structure and Magnetic Property of a Binuclear Nickel(Ⅱ) Complex

A new binuclear complex [Ni2（2,2＇-bpy）2（C8H3NO6）2（H2O）4] 1 （2,2＇-bpy = 2,2＇- bipyridine, C8H3NO6 = 4-nitrophthalate） has been synthesized by a hydrothermal reaction and characterized by X-ray single-crystal diffraction analysis. The complex crystallizes in triclinic, space group P1 with a = 7.206（2）, b = 10.337（4）, c = 12.480（4） , α = 89.887（11）, β = 77.033（9）, γ = 78.349（6）o, V = 886.3（5） 3, Z = 1, C36H30Ni2N6O16, Mr = 920.08, Dc = 1.724 g cm-3, F（000） = 472, μ = 1.152 mm-1, the final R = 0.0458 and wR = 0.1163 for 3372 observed reflections with I 2σ（Ⅰ）. The two Ni（Ⅱ） ions are bridged by two 4-nitrophthalates both in a bis-monodentate mode. Magnetic measurements reveal that the intramolecular exchange couplings in the dimer are ferromagnetic with 2J/k = 2.32 K, D =-1.44 K and g = 2.18.

Synthesis and Crystal Structure of a Novel Complex [Ag(NIT3Py)_3]·(ClO_4)(H_2O)

A novel complex [Ag(NIT3Py)3]?(ClO4)(H2O) has been synthesized and structurally characterized by X-ray diffraction method. It crystallizes in the rhombohedral system, space group R 3 with a = 15.8227(17), b = 15.8227(17), c = 31.445(3) ?, γ = 120°, V = 6817.8(12) ?3, Dc = 1.370 g/cm3, Z = 6, μ = 0.566 mm-1, Mr = 937.18, F(000) = 2916, R = 0.0715, wR = 0.2115 and GOF = 1.086. The structure consists of Ag(NIT3Py)3+ cation moiety, one water molecule and one perchloric ion. The Ag(I) ion is in a trigonal planar coordination environment formed by three nitrogen atoms from three NIT3Py ligand molecules.

Ground state singlet-to-triplet conversion of copper corrole radical byβ-benzo-fusion

Materials with facilely tunable spin configurations based on metal-radical coordination systems have potential applications for electronics and spintronics.Here,we report the ground state conversion of copper corrole radicals from singlet to triplet via the extension of theπ-conjugation system by benzo-fusion at theβ-position of corrole ligand.NMR spectroscopy,SQUID measurements and computational studies all support the ferromagnetic coupling between the Cu(II)center and corroleπ-radical of benzo-fused copper corrole 2-Cu,which is in sharp contrast with the antiferromagnetic coupling in regular non-extended copper corroles.The triplet 2-Cu is highly stable in air,and X-ray diffraction analysis revealed its unique highly planar corrole macrocycle.This work offers a promising strategy for creating high-spin systems in non-innocent metallocorroles.