Synthesis,crystal structures,and magnetic properties of two cyano-bridged tungstate(V)-manganese(II) bimetallic magnets

The reaction of manganese acetate with octacyanotungastate in an aqueous solution of concentrated acetic acid gives two new three-dimensional cyano-bridged manganese(II)-tungstate(V) bimetallic assemblies, [Mn(II)(2)(H(2)O)(2)(CH(3)COO)][W(V)(CN)(8)].2H(2)O (1) (tetragonal space group I4/mcm, a = b = 11.9628(9) A, c = 13.367(2) A, and Z = 4) and Cs(I)(0.5)Mn(II)(2)[W(V)(CN)(8)](CH(3)CO(2))(1.5).H(2)O (2) (monoclinic space group C2/c, a = 16.274(2) A, b = 22.948(6) A, c = 13.196(1) A, beta = 128.040(6) degrees, and Z = 8). In complex 1, W(V)(CN)(8) adopts a square antiprismatic geometry, and each CN group coordinates to the Mn(II) ions forming W-Mn(4)-W-Mn(4)-...columnar linkages where four sites on the Mn(II) ion with octahedral geometry are occupied by CN groups. The columns are parallel and interlock, yielding a network structure. Complex 2 contains two different coordination geometries for W(V)(CN)(8), namely, square antiprismatic and dodecahedral. The columnar structures appear also in 2, where the Mn(II) ions in two different environments provide three and four coordinated sites to the CN groups. The columns are bridged by both dodecahedral W(V)(CN)(8) groups and acetates. Cs ions were intercalated in the lattice by the formation of short attractive contacts with the acetates. The field-cooled magnetization, ac susceptibility, and the field dependence of magnetization measurements show that both 1 and 2 are ferrimagnets with ordering temperatures 40 and 45 K, respectively. The investigation of the magnetostructural correlation shows that the ferrimagnetic ordering in 1 and 2 are attributed to the dominant antiferromagnetic exchange pathways d(z)2(W)-d(x')(y')(Mn) and d(x)2(-y)2(W) - d(x')(y')(Mn).     

Synthesis,crystal structure and magnetic properties of N -benzesulfonyl-L-glutamic acid-bridged binuclear nickel(II) complex

N-benzesulfonyl-L-glutamic acid-bridged binuclear nickel(II) complex, [Ni₂(Bs-Glu)₂(bipy)₂ (H₂O)₂]?·?3H₂O (Bs-Glu?=?N-benzesulfonyl-L-glutamic acid dianion, bipy?=?2,2′-bipyridine), has been synthesized and characterized structurally and magnetically. It crystallizes in the triclinic space group P 1. The α-carboxyl group coordinates to Ni(II) in a monodentate mode, while the γ-carboxyl group coordinates in a chelating mode. In the temperature range 2–300?K, magnetic measurements show that the exchange interaction of the two Ni(II) ions is antiferromagnetic, and the values for J, g are ?2.47?cm^?1 and 2.18, respectively.     

Synthesis,crystal structure and magnetic properties of a three-dimensional cyano-bridged heterometallic complex of manganese(II) and molybdenum(IV)

A bimetallic cyano-bridged complex {[Mn(ImH)(H₂O)₂]₂[Mo(CN)₈]·4H₂O} _n (ImH?=?imidazole) has been prepared and characterized. Single-crystal X-ray analysis reveals that the complex crystallizes in space group C2/c with a?=?15.665(2), b?=?14.616(2), c?=?12.307(2)?Å, α?=?90, β?=?108.31(1), γ?=?90°. The structure of the complex demonstrates a three-dimensional network through cyano-bridges. Each Mo(IV) atom has six –CN–Mn linkages and two terminal cyano ligands arranged in a square antiprismatic arrangement. The Mn(II) atom is in a distorted octahedral environment formed by three MoCN?→?Mn linkages along with one imidazole and two water molecules in cis configuration. Variable temperature magnetic susceptibility shows an antiferromagnetic coupling between Mn²⁺ ions through the NC–Mo^IV–CN diamagnetic bridges within the three-dimensional network. The IR spectra have also been investigated.     

A cyano-bridged bimetallic ferrimagnet: Synthesis,X-ray structure and magnetic study

Mixing of trans-[Mn(cyclam)Cl₂]Cl (cyclam = 1,4,8,11-tetraazacyclotetradecane) and potassium hexacyanochromate (K₃[Cr(CN)₆]) aqueous solutions instantaneously yields a 1D infinite chain complex {[Mn(cyclam)(μ-CN)₂Cr(CN)₄]·H₂O}_n (1). The crystal structure of 1, crystallizing in the monoclinic system with space group P2₁/n has been solved from X-ray powder diffraction data following direct space approach and refined by the Rietveld method. The structure analysis of 1 reveals alternating [Cr(CN)₆]³⁻ and [Mn(cyclam)]³⁺ ions generating one-dimensional polymeric (–Cr–CN–Mn–NC–)_n chain propagating along the [0 0 1] direction. The coordination environment of both the metal ions, Mn(III) and Cr(III), is octahedral. While a notable distortion in the coordination environment around Mn(III) centers was observed in complex 1, Cr(III) centers have suffered no such distortion. A ferrimagnetic interaction between the heterobimetallic centers was evidenced through variable temperature magnetic susceptibility measurements. The AC susceptibility measurement reveals that the compound 1 undergoes spontaneous ferrimagnetic ordering. Ferrimagnetic ordering has been rarely observed among the cyano-bridged compounds in the previous studies.     

Syntheses,crystal structures and magnetic properties of two new cyano-bridged bimetallic complexes

Transition Metal Chemistry - Two complexes [Fe(1,10-phen)2Ni(CN)4]n (1), {[Fe2(1,10-phen)4(CN)4Co2(1,10-phen)2Fe(CN)6]·2H2O}n (2) were prepared in the reaction of K3[Fe(CN)6] as cyanometalate...     

Synthesis,crystal structure and magnetic properties of a nickel(II) complex with pyridine-substituted nitronyl nitroxide radicals

The complex [Ni(NIT2Py)(PDA)(H₂O)]·(MeOH)(H₂O) [NIT2Py = 2-(2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; PDA = 2,6-pyridine dicarboxylic acid] has been prepared and structurally characterized. The Ni^II ion is in a distorted octahedral environment: one nitrogen atom and one oxygen atom from the NIT2Py, one nitrogen atom from the PDA and one oxygen atom from the H₂O in the basal plane; two oxygen atoms from the PDA in the axial position. The units of [Ni(NIT2Py)(PDA)(H₂O)] were connected as a one dimension chain by intermolecular hydrogen bonds. The complex exhibits intramolecular antiferromagnetic interactions between the Ni^II ion and the NIT2Py.     

Synthesis,crystal structure and magnetic properties of a nickel(II) complex containing a 2-pyridyl-substituted nitronyl nitroxide

A new complex of formula [Ni(NIT2Py)₂Cl(H₂O)]Cl·2CH₃OH, where NIT2Py is 2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, was synthesized and characterized structurally and magnetically. The structure consists of a [Ni(NIT2Py)₂Cl(H₂O)]⁺ ion, a chloride anion and two methanol molecules. The nickel(II) ion lies in a distorted octahedral environment; two nitrogen atoms and two oxygen atoms from NIT2Py ligands from the basal plane; one oxygen atom from a water molecule and one chloride anion occupy axial positions. Variable temperature magnetic susceptibility data show that there is strong antiferromagnetic coupling between the nickel(II) ion and nitronyl nitroxide radicals. The results suggest that the sign of the magnetic interaction depends on structural and ligand effects.     

A novel two-dimensional Ni(II) fumarato complex: Solvothermal synthesis, crystal structure and magnetic properties

Dark green single crystals of [Ni(fum)(phen)] (fum = fumarato, phen = 1,10-phenanthroline) (1) have been prepared under solvothermal conditions. Its crystal structure exhibits two dimensional (2D) character. The formed layers are built of dimers of crystallographically non-equivalent Ni(II) atoms linked by bridging fumarato ligands; one is of the μ₄-bridge type with both carboxylato groups coordinated in syn-anti fashion while in the second one both carboxylate groups form a chelate-like coordination. Both Ni(II) atoms are hexa-coordinated in the cis-NiO₄N₂ form; two coordination positions are occupied by a N-bonded chelate phen molecule and four positions by oxygen atoms from the fum ligands. The layers are interconnected by π–π interactions operating between aromatic rings of the phen ligands. The analysis of the experimental thermodynamic data supports the structural assumptions and showed that magnetic subsystem of 1 can be approximated by an array of antiferromagnetic S = 1 dimers with easy-axis uniaxial magnetic anisotropy D comparable to intradimer exchange coupling J, D/J ≈ 1 and D/k_B = −6 K. The specific heat data clearly indicate the absence of a phase transition to the ordered state at least at temperatures down to 2 K.     

Hexacyanocobaltate(III) anions as precursors of Co(II)-Ni(II) cyano-bridged multidimensional assemblies: hydrothermal syntheses, crystal and powder X-ray structures, and magnetic properties

Three novel cyanide-bridged heterobimetallic coordination polymers have been synthesized by hydrothermal routes, in superheated water solutions, by using K3[Co(CN)6], NiCl2.6H2O, and alpha-diimine ligands: [Ni(CN)4Co(phen)] (1; phen = 1,10-phenanthroline), [Ni(CN)4Co(2,2'-bipy)] (2; 2,2'-bipy = 2,2'-bipyiridine), and [Ni(CN)4Co(2,2'-bipy)2] (3). The isostructural compounds 1 and 2 contain a two-dimensional network with Co(II) centers octahedrally coordinated by one chelating 2,2'-bipy ligand and four cyanide groups of four distinct [Ni(CN)4]2-, through crystallographically equivalent, bridging units. Compound 3 contains one-dimensional zigzag chains in which the Co(II) ion is coordinated by two chelating 2,2'-bipy ligands and two cyanides from two different [Ni(CN)4]2- units cis to each other. These compounds have been fully characterized by single-crystal or unconventional powder X-ray diffraction analyses and variable-temperature magnetic measurements.     

Synthesis and crystal structure of nickel(II) complex based on 2-trifluoroacetylcycloalkanone benzoylhydrazones

The reaction of ethanol solutions of benzoylhydrazones of 2-trifluoroacetylcycloalkanones (H₂L) with a solution of nickel(II) acetate in aqueous ammonia in 1 : 1 ratio gave complexes NiL · NH₃ with square structure. The composition and structure of the complexes were determined by elemental analysis, IR and 1H NMR spectroscopy, and X-ray diffraction analysis.     

Effect of the semirigid capping ligand on the structure formation of cyano-bridged bimetallic assemblies: syntheses, crystal structures, and magnetic properties

The syntheses, crystal structures, and magnetic properties of three novel cyano-bridged bimetallic assemblies, [Ni(bpm)(2)](3)[Co(CN)(6)](2)x3.5H(2)O (1), [Co(bpm)(2)][Fe(CN)(5)NO]x2H(2)O (2), and [Co(bpm)(2)][Ni(CN)(4)] (3) (bpm = bis(1-pyrazolyl)methane), are reported. Complex 1 crystallizes in the tetragonal space group P4(3)2(1)2 with a = 12.800(5) A, b = 12.800(5) A, c = 42.80(3) A, V = 7012(6) A(3), and Z = 8. Complex 2 crystallizes in the chiral trigonal space group P3(2)21 with a = 11.9961(19) A, b = 11.9961(19) A, c = 16.062(5) A, gamma = 120 degrees , V = 2001.7(8) A(3), and Z = 3. Complex 1 is a trigonal bipyramidal complex in which three [Ni(bpm)(2)](2+) units are situated in the equatorial plane and are connected to the two apical [Co(CN)(6)](3)(-) units via three N ends of the cyanide groups. Complex 2 possesses a triangular left-handed helical chain structure composed of [Co(bpm)(2)](2+) linked by [Fe(CN)(5)NO](2)(-); the shortest intramolecular Co...Fe distance is 5.162 A. To the best of our knowledge, this is the first observation of a heteronuclear helical chain structure based on pentacyanonitrosylferrate(II). The structure of complex 3 is roughly determined by X-ray crystallograhy analysis to be a 1D zigzag chain. These structure variations, from a discrete cluster to a 1D helical chain and a 1D zigzag chain, rely on the semirigidity of the capping ligand bpm. Magnetic susceptibility measurements indicate that complex 1 has an intramolecular ferromagnetic interaction (J = 4.06 cm(-)(1)) between the nickel(II) ions; this is further confirmed by the magnetization measurements. In complexes 2 and 3, the cobalt(II) ions are located in a moderately strong field.     

A new zinc(II) complex containing nitronyl nitroxide radicals: Synthesis, crystal structure, and magnetic properties

A new one-dimensional dicyanamide bridged zinc(II) complex containing nitronyl nitroxide radicals [Zn(Hfac)₂(NIT-1′-MeBzIm)] (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, Hfac = hexafluoroacetylacetonate) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P2₁/c, Z = 4. Crystal data: C₂₅H₂₁F₁₂N₄O₆Zn, Mr = 766.83, a = 12.1812(13) Å, b = 16.8770(18) Å, c = 15.5230(16) Å, β = 98.009(2)°, V = 3160.1(6) ų, ρ _c = 1.612 g/cm³, μ(MoK _α) = 0.893 mm^?1, F(000) = 1540, R = 0.0925 and wR = 0.2652 for 5875 observed reflections with I > 2σ(I). The X-ray analysis reveals that the zinc(II) ion is six-coordinated with a distorted octahedral geometry. These units develop as 1D species by intermolecular hydrogen bonds. Magnetic investigation indicates the existence of weak intermolecular interactions is antiferromagnetic with J = ?1.35 cm^?1, where the spin Hamitonian is defined as H = ?2Σ _i,j J _i,j S _i S within the complex.     

Synthesis and crystal structure of dinuclear nickel (Ⅱ) complex

The crystal structure of Ni(Ⅱ) complex with 3-hydroxyl-1, 5-diazacycloheptane-N, N'-diacetate was determined by X-ray diffraction method. Crystal data for Ni2 (C9H14N2O5)2·2H2O: monoclinic, space group P21/n, a = 1.1717(5), b = 0.9794(3), c = 1.2971(2) nm, β= 96.62(3), V= 1.4786(7) nm3, Dc = 1.377 g/cm3, Z = 2,μ=13.321 cm-1 (Mo-Kα), F(000)=640. The final R and Rw are 0.075 and 0.089 respectively. The Ni(Ⅱ) ion forms 2:2 complex with ligand. Two ligands are bridged by two Ni(Ⅱ) atoms which are bridged by two O atoms. Every Ni(Ⅱ) is coordinated by two N atoms and four 0 atoms. The coordination polyhedron of the Ni(Ⅱ) ion is a distorted octahedron.     

Synthesis, crystal structures, and magnetic properties of a new nickel(II) complex with nitronyl nitroxide

A new nickel(II) complex [Ni(NIT-1′-MeBzIm)₂(H₂O)₂] · ClO₄ · H₂O (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been prepared and structurally characterized by single-crystal X-ray diffraction. Complex I crystallizes in monoclinic, space group C2/c, Z = 4. Crystal data: C₃₀H₄₆N₈O₁₆ClNi, Mr = 869.06, a = 13.958(3), b = 15.904(4), c = 18.514(5) Å, β = 101.047(3)°. The X-ray analysis reveals that Ni²⁺ ion resides in a distorted octahedron center, the complex was linked by intermolecular hydrogen bonds, resulting in a 2D network configuration. Magnetic investigation indicates the existence of interamolecular interactions is antiferromagnetic with J = ?40.76 cm^?1.     

Synthesis,crystal structure,and magnetic properties of a linear trinuclear Cu(II) complex

A new linear trinuclear Cu(II) complex, [Cu₃(NTA)₂(4,4′-bpt)₄(H₂O)₂]?·?10H₂O (H₃NTA?=?nitrilotriacetic acid, 4,4′-bpt?=?4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole) (1), was obtained from evaporation of an aqueous solution containing Cu(NO₃)₂?·?6H₂O, 4,4′-bpt, nitrilotriacetic acid (H₃NTA), and NaOH. 1 was characterized using single-crystal X-ray diffraction, IR, and elemental analysis. In the trimer, the three linear copper ions are bridged by two NTA carboxylate groups in a syn–anti conformation and connected by 4,4′-bpt to produce a 1-D array. Temperature-dependent magnetic susceptibilities reveal the presence of weak antiferromagnetic exchange between metal centers.     

Synthesis,crystal structure,and magnetic properties of 1D Azido-bridged copper(II) complex

A novel copper(II)-azide complex of [Cu₂(DMAP)₂(μ-1,1-N₃)₂(μ-1,3-N₃)₂]_n (DMAP = 4-(dimethylamino)pyridine) has been synthesized and characterized by IR spectra, X-ray diffraction, elemental analysis, and magnetism measurement. The complex reveals a 1D ladder-like chain structure, in which two μ-1,1-N₃ and two μ-1,3-N₃ bridges form a dimeric unit of [Cu₂(DMAP)₂(μ-1,1-N₃)₂(μ-1,3-N₃)₂] and are then connected to each other from the tail nitrogens of two asymmetric μ-1,3-N₃ bridges to generate a chain structure that stacks in the cell to construct the 3D crystal. The Cu atom is five-coordinated by azide anions to form a distorted square-pyramid of CuN₅ (τ = 0.2667). Magnetic susceptibility of complex exhibits a ferromagnetic interaction between the copper(II) ions through two kinds of azido-bridges. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.