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1.
《Journal of Coordination Chemistry》2012,65(24):2747-2754
A mixed-valence cyano-bridged CuII/CuI 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. 相似文献
2.
Dawei Feng Cheng Wang Wentai Cheng Guobao Li Shujian Tian Fuhui Liao Ming Xiong Jianhua Lin 《Solid State Sciences》2009,11(4):845-851
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. 相似文献
3.
Ben Yahia H Gaudin E Darriet J Banks M Kremer RK Villesuzanne A Whangbo MH 《Inorganic chemistry》2005,44(9):3087-3093
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. 相似文献
4.
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. 相似文献
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6.
《Journal of solid state chemistry》1986,62(1):16-25
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 < TC < 4.2 K. The variation of Hint has been monitored by Mössbauer spectroscopy in the temperature range 1.3 < T < 4.2 K. 相似文献
7.
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. 相似文献
8.
B. Machura A. Świtlicka J. Mroziński J. Kłak R. Kruszynski J. Kusz D. Tabak 《Polyhedron》2009,28(17):3774-3780
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. 相似文献
9.
Yuan Ai-Hua Lu Lu-De Shen Xiao-Ping Chen Li-Zhuang Yu Kai-Bei 《Transition Metal Chemistry》2003,28(2):163-167
A cyanide-bridged FeIII–FeII mixed-valence assembly, [FeIII(salen)]2[FeII(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 [—FeII—CN—FeIII—NC—]4 units with dimensions: FeII—C = 1.942(7) Å, C—N = 1.139(9) Å, FeIII—N = 2.173(6) Å, FeII—C—N = 178.0(6)°, FeIII—N—C = 163.4(6)°. The FeII—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 FeIII–FeIII exchange integral of –0.033 cm–1. 相似文献
10.
J Martínez-Lillo L Cañadillas-Delgado J Cano F Lloret M Julve J Faus 《Chemical communications (Cambridge, England)》2012,48(74):9242-9244
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. 相似文献
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Belik AA Azuma M Matsuo A Whangbo MH Koo HJ Kikuchi J Kaji T Okubo S Ohta H Kindo K Takano M 《Inorganic chemistry》2005,44(19):6632-6640
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. 相似文献
13.
Nuss J Señaris-Rodriguez MA Dasari PL Stahl M Jansen M 《Journal of the American Chemical Society》2012,134(28):11734-11739
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. 相似文献
14.
R. V. Shpanchenko A. A. Tsirlin J. Hadermann E. V. Antipov 《Russian Chemical Bulletin》2008,57(3):552-556
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. 相似文献
15.
Fatma Aytan Kiliçarslan Bahadir Keskin İbrahim Erden 《Journal of Coordination Chemistry》2017,70(15):2671-2683
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. 相似文献
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HB Yahia M Shikano S Koike K Tatsumi H Kobayashi H Kawaji M Avdeev W Miiller CD Ling J Liu MH Whangbo 《Inorganic chemistry》2012,51(16):8729-8738
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. 相似文献
18.
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) Å3. 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. 相似文献
19.
《Solid State Sciences》2001,3(5):559-568
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. 相似文献
20.
《Journal of Coordination Chemistry》2012,65(8):1207-1217
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. 相似文献