Synthesis,crystal structure,magnetic properties and electrochemical behavior of the mixed valence compound [CuI(CN)3CuII(dipn)]

A mixed-valence cyano-bridged Cu^II/Cu^I complex, 1, has been prepared. Complex 1 was fully characterized spectroscopically (UV-Vis and IR), and its structure was determined by X-ray crystallography. The magnetic property was measured in the temperature range 2–300?K. Electrochemical studies of 1 reveal a one-electron oxidation-reduction process associated with the Cu(II)/Cu(I) couple.     

Synthesis,crystal structure,and magnetic properties of K4Mn3(HPO4)4(H2PO4)2

A new layered compound, K₄Mn₃(HPO₄)₄(H₂PO₄)₂ (1), has been synthesized under hydrothermal conditions. It crystallizes in the monoclinic space group P2₁/n with a = 8.874(2) Å, b = 6.554(1) Å, c = 18.075(4) Å, and β = 93.39(3)°. The structure consists of zigzag [Mn₃O₁₄]_n chains of edge-sharing MnO₆ octahedrons and MnO₇ pentagonal bi-pyramids, which form layers of formula [Mn₃(HPO₄)₄(H₂PO₄)₂]^4? in the ab plane via H₂PO₄ and HPO₄ units with vertex-sharing. Potassium ions lie between these layers. Magnetic measurements indicate Curie–Weiss behavior above 6 K for 1. A Heisenberg model, with alternating exchange interactions J₁J₁J₂… within the chain and exchange interactions J₃J₃… between the chains, is proposed to describe the magnetic behavior.     

Synthesis, crystal structure, magnetic properties, and electronic structure of the new ternary vanadate CuMnVO4

A new magnetic oxide, CuMnVO4, was prepared, and its crystal structure was determined by single-crystal X-ray diffraction. The magnetic properties of CuMnVO4 were characterized by magnetic susceptibility and specific heat measurements, and the spin exchange interactions of CuMnVO4 were analyzed on the basis of spin-polarized electronic band structure calculations. CuMnVO4 contains MnO4 chains made up of edge-sharing MnO6 octahedra containing high-spin Mn2+ cations. Our work shows that CuMnVO4 undergoes a three-dimensional antiferromagnetic transition at approximately 20 K. Both the intrachain and interchain spin exchanges are antiferromagnetic, and the interchain spin exchange is not negligible compared to the intrachain spin exchange.     

Synthesis,structure and characterization of a new trinuclear magnetic semiconductor PbI4[Cu(Me2dtc)(bipy)]2

A new trinuclear magnetic lead iodide semiconductor PbI₄[Cu(Me₂dtc)(bipy)]₂ (Me₂dtc = N,N-dimethyldithiocarbamate, bipy = 2,2′-bipyridine) has been synthesized, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2₁/c with a = 22.2137(11) Å, b = 11.3687(4) Å, c = 15.3382(8) Å, β = 102.372(3)°, Z = 4, V = 3783.6(3) Å³. It is built up by [PbI₄S₂] octahedron linked with two [CuIS₂N₂] square pyramids through common edges. The adjacent molecules stack with each other to form a two-dimensional (2D) layer along ab plane via the π–π stacking interactions between aromatic groups of bipy ligands. Then the 2D layers are further extended into a three-dimensional structure through hydrogen bonding interactions. The temperature dependence of the electrical conductivity indicates that this compound exhibits semiconducting character. The title brown–black compound has an optical bandgap of 1.26 eV, and the variable-temperature magnetic susceptibility measurement indicates weak antiferromagnetic behavior with J = ?1.06 cm^?1.     

配合物[Co(PMBP)2(MeOH)(EtOH)]的合成、表征及晶体结构

在醇溶液中合成了标题配合物[Co(PMBP)2(MeOH)(EtOH)](HPMBP=1-phenyl-3-methyl-4-benzoyl-pyrazolone-5),并进行了元素分析、红外光谱、摩尔电导率、X-射线衍射等表征.结果表明此配合物属单斜晶系,空间群为P2(1)/n,晶胞参数为:a=13.802(2),b...     

The crystal structure and magnetic properties of the synthetic langbeinite KBaFe2(PO4)3

Powder neutron diffraction data have been used to refine the crystal structure of KBaFe₂(PO₄)₃ at 4.2 K; space group P2₁3, a₀ = 9.8732(1) Å. The material is isostructural with the mineral langbeinite, having two crystallographically distinct, octahedrally coordinated Fe³⁺ ions in the asymmetric unit. Mössbauer effect spectroscopy and magnetic susceptibility measurements show that KBaFe₂(PO₄)₃ orders as an L-type ferrimagnet with 3.9 < T_C < 4.2 K. The variation of H_int has been monitored by Mössbauer spectroscopy in the temperature range 1.3 < T < 4.2 K.     

Synthesis,crystal structure,and magnetic properties of the oxometallates KBaMnO4 and KBaAsO4

Single crystals of KBaMnO₄ and KBaAsO₄ were grown using the hydroflux method and characterized by single crystal X-ray diffraction. Both compounds crystallize in the orthorhombic space group Pnma with a = 7.7795(4) Å, b = 5.8263(3) Å, and c = 10.2851(5) Å for the manganate and a = 7.7773(10) Å, b = 5.8891(8) Å, and c = 10.3104(13) Å for the arsenate. The materials exhibit a three-dimensional crystal structure consisting of isolated MnO₄³⁻ or AsO₄³⁻ tetrahedra, with the charge balance maintained by K⁺ and Ba²⁺. Each tetrahedron is surrounded by six K⁺ and five Ba²⁺, and shares its corner/edge with KO₁₀ polyhedra and corner/edge/face with BaO₉ polyhedra, respectively. The crystal growth, crystal structure and magnetic properties are discussed.     

Synthesis,spectroscopic characterization,X-ray structure and magnetic properties of [Cu(hmquin-7-COOH)2(MeOH)] complex

The reaction of copper(II) chloride dihydrate and 8-hydroxy-2-methylquinoline-7-carboxylic acid (Hhmquin-7-COOH) leads to [Cu(hmquin-7-COOH)₂(MeOH)]. The compound has been studied by IR, UV–Vis, EPR spectroscopy and X-ray crystallography. X-ray studies confirm bidentate coordination mode of the hmquin-7-COOH anions via the pyridine nitrogen atom and deprotonated hydroxyl group. The COOH groups of the hmquin-7-COOH ligands are potentially available for further conjugation. The title complex has been additionally studied by magnetic measurement. The TDDFT/PCM calculations have been employed to discuss the electronic spectrum of [Cu(hmquin-7-COOH)₂(MeOH)] in more detail.     

Synthesis,crystal structure and magnetic properties of a two-dimensional mixed-valence assembly [Fe(salen)]2[Fe(CN)5NO]

A cyanide-bridged Fe^III–Fe^II mixed-valence assembly, [Fe^III(salen)]₂[Fe^II(CN)₅NO] [salen = N,N-ethylenebis(salicylideneiminato)dianion], prepared by slow diffusion of an aqueous solution of Na₂[Fe(CN)₅NO] · 2H₂O and a MeOH solution of [Fe(salen)NO₃] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [—Fe^II—CN—Fe^III—NC—]₄ units with dimensions: Fe^II—C = 1.942(7) Å, C—N = 1.139(9) Å, Fe^III—N = 2.173(6) Å, Fe^II—C—N = 178.0(6)°, Fe^III—N—C = 163.4(6)°. The Fe^II—N—O bond angle is linear (180.0°). The variable temperature magnetic susceptibility, measured in the 4.8–300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an Fe^III–Fe^III exchange integral of –0.033 cm^–1.     

A heteropentanuclear oxalato-bridged [Re(IV)(4)Gd(III)] complex: synthesis, crystal structure and magnetic properties

The compound (NBu(4))(5)[Gd(III){Re(IV)Br(4)(μ-ox)}(4)(H(2)O)]·H(2)O (1), with intramolecular antiferromagnetic coupling, is the first Re(iv) system incorporating a 4f ion.     

Investigation of the crystal structure and the structural and magnetic properties of SrCu2(PO4)2

SrCu2(PO4)2 was prepared by the solid-state method at 1153 K. Its structure was solved by direct methods in the space group Pccn (No. 56) with Z = 8 from synchrotron X-ray powder diffraction data measured at room temperature. Structure parameters were then refined by the Rietveld method to obtain the lattice parameters, a = 7.94217(8) A, b = 15.36918(14) A, and c = 10.37036(10) A. SrCu2(PO4)2 presents a new structure type and is built up from Sr2O16 and Cu1Cu2O8 units with Cu1...Cu2 = 3.256 A. The magnetic properties of SrCu2(PO4)2 were investigated by magnetic susceptibility, magnetization up to 65 T, Cu nuclear quadrupole resonance (NQR), electron-spin resonance, and specific heat measurements. With spin-dimer analysis, it was shown that the two strongest spin-exchange interactions between Cu sites result from the Cu1-O...O-Cu2 and Cu2-O...O-Cu2 super-superexchange paths with Cu1...Cu2 = 5.861 A and Cu2...Cu2 = 5.251 A, and the superexchange associated with the structural dimer Cu1Cu2O8 is negligible. The magnetic susceptibility data were analyzed in terms of a linear four-spin cluster model, Cu1-Cu2-Cu2-Cu1 with -2J(1)/kB = 82.4 K for Cu1-Cu2 and -2J(2)/k(B) = 59 K for Cu2-Cu2. A spin gap deduced from this model (Delta/kB = 63 K) is in agreement with that obtained from the Cu NQR data (Delta/kB = 65 K). A one-half magnetization plateau was observed between approximately 50 and 63 T at 1.3 K. Specific heat data show that SrCu2(PO4)2 does not undergo a long-range magnetic ordering down to 0.45 K. SrCu2(PO4)2 melts incongruently at 1189 K. We also report its vibrational properties studied with Raman spectroscopy.     

Synthesis, crystal structure and magnetic properties of the new one-dimensional manganate Cs3Mn2O4

Cs(3)Mn(2)O(4), a new member of the small family of ternary manganese (II/III) mixed-valent compounds, has been synthesized via the azide/nitrate route and studied using powder and single crystal X-ray diffraction, magnetic susceptibility measurements and density functional theory (DFT). Its crystal structure (P2(1)/c, Z = 8, a = 1276.33(1) pm, b = 1082.31(2) pm, c = 1280.29(2) pm, β = 118.390(2)°) is based on one-dimensional MnO(2)(1.5-) chains built up from edge-sharing MnO(4) tetrahedra. The title compound is the first example of an intrinsically doped transition metalate of the series A(x)MnO(2), (A = alkali metal) where a complete 1:1 charge ordering of Mn(2+) and Mn(3+) is observed along the chains (-Mn(2+)-Mn(3+)-Mn(2+)-Mn(3+)-). From the magnetic point of view it basically consists of ferrimagnetic MnO(2) chains, where the Mn(2+) and Mn(3+) ions are strongly antiferromagnetically coupled up to high temperatures. Very interestingly, their long-range three-dimensional ordering below the Néel temperature (T(N)) ~12 K give rise to conspicuous field dependent magnetic ordering phenomena, for which we propose a consistent picture based on the change from antiferromagnetic to ferromagnetic coupling between the chains. Electronic structure calculations confirm the antiferromagnetic ordering as the ground state for Cs(3)Mn(2)O(4) and ferrimagnetic ordering as its nearly degenerate state.     

Synthesis and crystal structure of new titanyl phosphate Sr2TiO(PO4)2

New strontium titanyl phosphate Sr₂TiO(PO₄)₂ (1) was synthesized and characterized by X-ray powder diffraction, electron diffraction, high-resolution electron microscopy, and band structure calculations. Titanyl phosphate 1 is isostructural with vanadyl phosphate Sr₂VO(PO₄)₂ and has a layered structure. The titanium atoms are shifted from the centers of the TiO₆ octahedra and form short (1.74 Å) titanyl bonds. The structure of 1 is an unusual example of the disordered orientation of the chains formed by TiO₆ octahedra in complex titanium phosphates.     

Synthesis,characterization and electrochemical properties of new phthalocyanines

The chemical synthesis and characterization with spectroscopic and electrochemical properties of [bis(4-fluorophenyl)-methoxy]-substituted metallo-phthalocyanines were reported for the first time. The new phthalocyanines have been characterized by elemental analysis, UV-Vis, FT-IR, and mass spectroscopies. The aggregation behavior of the phthalocyanine compounds was investigated in different solvents and concentrations. It is found that the fluoro substituents of peripherally Co and Cu complexes are examined and induce a shift to the redox processes toward the negative potentials and formed more reversible processes. Metal-based reduction and oxidation reactions were obtained for the Co(II) complex, whereas Cu(II) complexes exhibited Pc-ring-based electron-transfer reactions. The voltammetric measurements supported the proposed structure of the complexes.     

Synthesis and Characterization of the Crystal Structure and Magnetic Properties of the New Fluorophosphate LiNaCo[PO(4)]F

The new compound LiNaCo[PO(4)]F was synthesized by a solid state reaction route, and its crystal structure was determined by single-crystal X-ray diffraction measurements. The magnetic properties of LiNaCo[PO(4)]F were characterized by magnetic susceptibility, specific heat, and neutron powder diffraction measurements and also by density functional calculations. LiNaCo[PO(4)]F crystallizes with orthorhombic symmetry, space group Pnma, with a = 10.9334(6), b = 6.2934(11), c = 11.3556(10) ?, and Z = 8. The structure consists of edge-sharing CoO(4)F(2) octahedra forming CoFO(3) chains running along the b axis. These chains are interlinked by PO(4) tetrahedra forming a three-dimensional framework with the tunnels and the cavities filled by the well-ordered sodium and lithium atoms, respectively. The magnetic susceptibility follows the Curie-Weiss behavior above 60 K with θ = -21 K. The specific heat and magnetization measurements show that LiNaCo[PO(4)]F undergoes a three-dimensional magnetic ordering at T(mag) = 10.2(5) K. The neutron powder diffraction measurements at 3 K show that the spins in each CoFO(3) chain along the b-direction are ferromagnetically coupled, while these FM chains are antiferromagnetically coupled along the a-direction but have a noncollinear arrangement along the c-direction. The noncollinear spin arrangement implies the presence of spin conflict along the c-direction. The observed magnetic structures are well explained by the spin exchange constants determined from density functional calculations.     

A new polymorph of NH4V3O7: Synthesis,structure, magnetic and electrochemical properties

NH₄V₃O₇ micro-sized crystals have been successfully synthesized via a conventional hydrothermal synthesis route. The products were characterized by means of X-ray and neutron powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, static magnetization measurements, and electrochemical cycling. The diffraction patterns of NH₄V₃O₇ can be indexed in the monoclinic space group P2₁ with the cell parameters a = 12.247(5) Å, b = 3.4233(10) Å, c = 13.899(4) Å, β = 87.72(3)°, and V = 582.3(4) ų. The crystal structure is built up of (V₃O₇)-layers with V⁴⁺-and V⁵⁺-ions, which occupy oxygen octahedra and tetrahedra, respectively. The (V₃O₇)-layers are bonded by (NH₄)⁺ -ions. Analysis of the magnetization data confirms that 2/3 of the V-ions are 4 + associated with S = 1/2. Roughly half of them are strongly coupled to antiferromagnetic dimers (J = 720 K), the other half is only weakly (J of several 10 K) antiferromagnetically interacting. Electrochemical cycling shows reversible lithium de-/intercalation into the layered NH₄V₃O₇ host structure with an initial specific discharge capacity of 310 mAh/g at 7 mA/g.     

Synthesis,crystal structure,magnetic properties and spin glass behaviour of the new ternary compound Cr4TiSe8

The new ternary selenide Cr₄TiSe₈ crystallises in the V₅S₈ type structure. The determination of the metal atom distribution over the three crystallographically independent sites using neutron scattering experiments reveals that the Ti atoms exclusively occupy the sites within the full metal atom layers with a pronounced preference for one of the two possible sites. The magnetic properties in the high temperature region exhibit Curie–Weiss behaviour with a paramagnetic Curie temperature θ of −300(5) K indicating strong antiferromagnetic exchange interactions. Between about 100 and 300 K the susceptibility data pass a very broad maximum and a qualitatively explanation is presented that base on antiferromagnetic exchange interactions between Cr atoms forming linear trimers, dimers, or Cr atoms being isolated. Below about 50 K the zero field cooled and field cooled susceptibility curves diverge suggesting spin glass behaviour. In the low temperature neutron diffraction patterns no additional peaks are observed which gives further evidence for the occurrence of a spin glass. Below 120 K the background of the diffraction patterns becomes modulated due to the short range magnetic interactions with sizes of the domains ranging from about 15 to 38 Å. Low temperature single crystal X-ray investigations show a remarkable change of the contraction of the lattice parameters below about 220 K that may be due to the onset of the strong magnetic exchange interactions.     

Synthesis,structure determination,and magnetic properties of pentakis[ bis (hexafluoroacetylacetonato)1,2,4-triazinecopper(II)]

Reaction of bis(hexafluoroacetylacetonato)copper(II) hydrate with 1,2,4-triazine (tz) in dichloromethane yields pentakis[bis(hexafluoroacetylacetonato)triazinecopper(II)] [Cu(hfac)₂(tz)]₅ (hfac = hexafluoroacetylacetonate) (1). The complex crystallizes in the triclinic space group P-1, with cell parameters a = 11.4124(5), b = 13.3405(5), c = 16.1794(7) Å, α = 93.360(2)°, β = 108.700(2)°, γ = 100.293(2)° at 120(1) K. In the complex, the copper(II) ions show three types of coordination polyhedra: square planar, square pyramidal, and octahedral (4 + 2). The tz ligand also shows different coordination modes (bridging and monodentate). In addition, disorder is observed in the triazine molecule, either through non-crystallographic two-fold rotation about the longitudinal N,N-axis, or with respect to a crystallographic center of symmetry. The crystal structure of 1 consists of alternating trimers and dimers. The weak coordination of the tz molecules results in negligible magnetic exchange through the ring.