Synthesis, crystal structure and properties of a new heptamolybdate (NH4)6H2[Cu(C2O4)2(Mo7O24)] · 9H2O

An interesting heptamolybdate (NH₄)₆H₂[Cu(C₂O₄)₂(Mo₇O₂₄)] · 9H₂O (I) was prepared by convenational method in an aqueous solution and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. Crystal data for I: monoclinic, space group P2₁/m with a = 10.1460(5), b = 18.2616(9), c = 10.4994(5) ?, β = 94.3410(10)°, and Z = 2. X-ray structure analysis revealed the complexes to contain a copper center in an octahedral coordination mode bound to two [C₂O₄]²⁻ anios via the oxygen atoms and two oxygen atoms of the new heptamolybdate species. The zigzag chain structure of I is constructed by [Cu(C₂O₄)₂(Mo₇O₂₄)] units via Mo-O-Cu-O-Mo linkers.     

Synthesis and crystal structure of sodium isopolyvanadate [Na2(H2O)8]2H2[V10O28] · 4H2O

The sodium hydrogen oxovanadate [Na₂(H₂O)₈] ₂H₂[V₁₀O₂₈] · 4H₂O was synthesized and studied by TGA, X-ray diffraction, and NMR and IR spectroscopy. The crystals are triclinic, space group P $ \bar 1 $ \bar 1 , a = 8.545(7) ?, b = 10.827(2) ?, c = 11.627(2) ?, α = 105.48(3)°, β = 99.38(3)°, γ = 101.29(3)°, V = 989.9(3) ?³, ρ(calcd) = 2,381 g/cm³, Z= 1.     

Rhenium(IV)–copper(II) heterobimetallic complexes: Synthesis,crystal structure and magnetic properties

Two Re(IV)–Cu(II) heterometallic complexes {(CuL_α)[ReCl₄(ox)]}_n (where L_α = N-meso-5,12-Me₂-7,14-Et₂-[14]-4,11-dieneN₄), 1, and (CuL_β)[ReCl₄(ox)] (L_β = N-rac-5,12-Me₂-7,14-Et₂-[14]-4,11-dieneN₄N-rac-5,12-Me₂-7,14-Et₂-[14]-4,11-dieneN₄), 2, were synthesized. The [CuL²⁺] macrocyclic cation is coordinated from above and below by [ReCl₄(ox)]²⁻ units through the chloro-ligands and creates a chloro-bridged heterometallic Re^IV–Cu^II one-dimensional zig-zag chain. Compound 2 can be viewed as a heterobimetallic dinuclear unit, in which the Re(IV)-Cu(II) centers are linked by an oxalato bridge. The magnetic behavior of 1 and 2 has been investigated over the temperature range 1.8–300 K. Compound 1 behaves like a ferrimagnetic {Re(IV)–Cu(II)} bimetallic, one-dimensional chain with intrachain antiferromagnetic coupling. Compound 2 shows a weak antiferromagnetic interaction within the [Re(IV)–Cu(II)] unit along with a strong single-ion anisotropy, D(Re) = −63 cm⁻¹.     

A novel polybromide complex of bismuth – (Et4N)3{[Bi2Br9](Br2)}: synthesis and structural features

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A new polyoxovanadium supramolecular complex [(N(CH2CH2NH3)3)2(V6O18)]·3H2O: Synthesis, structure, and thermal properties

A new polyoxovanadium supramolecular complex, [(N(CH₂CH₂NH₃)₃)₂(V₆O₁₈)]·3H₂O (1), was synthesized as a crystalline product from aqueous solution at room temperature. From single crystal X-ray structural analysis, the complex is monoclinic, space group P2₁/n, with a = 15.878(2) ?,b = 11.3309(15) ?, c = 19.469(3) ?, β = 102.244(2)°, V = 3423.0(8) ?³, Z = 4, final R = 0.0469. The crystal structure comprises 1D spiral vanadate chain as the oxide moiety, doubly protonated cations of tris(2-aminoethyl)amine (tren) and three lattice molecules of water. There are numerous H bonds in the structure connecting the polyoxovanadium anion moiety, protonated tren cation and lattice water molecules; the average O...O and N...O distances are 2.753 ? for O-H...O and 2.879 ? for N-H...O, respectively. Original Russian Text Copyright ? 2009 by J. Li, Y. H. Xing, M. F. Ge, C. G. Wang, Z. P. Li, and S. Y. Niu The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 553–559, May–June, 2009.     

Synthesis, crystal structure and luminescence of a novel metal-organic polymer {Cd2(C4H2O4)2(C4H6N2)2(H2O)2 · 2H2O}n

The novel 3D coordination polymer {Cd₂(C₄H₂O₄)₂(C₄H₆N₂)₂(H₂O)₂ · 2H₂O} _n (I) has been synthesized and characterized by standard solid state methods including single-crystal X-ray crystallography. The compound crystallizes in triclinic space group P [`1]\bar 1 with a = 8.589(4), b = 10.585(3), c = 13.094(1) ?, α = 84.91(4)°, β = 79.21(0)°, γ = 83.76(4)°, V = 1159.5(1) ?³, Z = 2. The fumaric acid acts as a multimodal bridging ligand in the polymer unit. One of the fumaric acid ligands tridentately chelates to two Cd²⁺ cations in the same dinuclear unit, while the other bidentately chelates to two Cd²⁺ cations in another dinuclear unit. The two metal centers possess slightly distorted pentagonal bipyramid geometry with four Cd {(μ₄-fumarato)-(μ₂-fumarato)-bis(2-methylimidazolyl)-diaqua} units joining together to form a 28-membered ring. The whole molecule exhibits a through channel along y-axis and 2D layers in xz plane. With hydrogen bond and π-π interaction, the 2D layers construct a 3D microporous network.     

Synthesis, crystal structure and magnetic properties of a novel manganese(II)-nitronyl nitroxide-azido(μ_(1,1) and μ_(1,3)) one-dimensional complex

A novel one-dimensional manganese(Ⅱ) complex containing nitronyl nitroxide radical [Mn2(IM2-py)2(Ac)2((μ1.1-N3)(μ1,3-N3) . EtOH]n was synthesized and characterized structurally and magnetically. It crystallizes in the monoclinic space group p21/n. Each Mn(Ⅱ) ion is six-coordinated in a distorted octahedral environment. The two N atoms of the nitronyl nitroxide radical and the two O atoms of acetate ligands are in the equatorial plane, whereas the two different azido bridging ligands are in trans axial position. Mn(Ⅱ) ions are linked by nitrogen atom of μ1,1-azido and oxygen atoms of two carboxy groups to form a Mn-Mn unit. Mn-Mn units are linked by azido ligands through u1,3 bridging style to form a one-dimensional chain. The compound is connected by the coordination bonds,π-π interactions and hydrogen bonds as a three-dimensional structure. Magnetic susceptibility data support that there are stronger antiferromagnetic interactions between the radical and Mn(Ⅱ) ion, weak antiferromagnetic inter     

Acid nickel oxovanadate [Ni(H2O)6]2[H2V10O28] · 6H2O: Synthesis, IR spectra, thermal analysis, and crystal structure

Acid nickel oxovanadate, [Ni(H₂O)₆]₂[H₂V₁₀O₂₈] · 6H₂O (I) was synthesized and studied by X-ray diffraction analysis, thermogravimetry, powder X-ray diffraction, and IR spectroscopy. The crystals are triclinic: space group , a = 8.869(2) ?, b = 10.869(2) ?, c = 11.116(2) ?, α = 65.14(3)°, β = 74.11(3)°, γ = 70.47(3)°, V = 907.41 ?³, ρ(calcd.) = 2.56 g/cm³, Z = 1. Original Russian Text ? G.Z. Kaziev, A.V. Oreshkina, S.H. Quinones, D.A. Alekseev, V.E. Zavodnik, T.Yu. Glazunova, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 8, pp. 593–598.     

New assembly of organic components and transition metal complexes based on [VMo6O22]3? and [V2Mo6O26]6? building blocks: syntheses, crystal structures, and magnetic properties

Two new molybdovanadates, (H₃NCH₂CH₂NH₃)₃ [Mo₆VO₂₂(CH₃COO)₃]·5H₂O (1) and (H₃NCH₂CH₂NH₃)₂{(Mo₆V₂O₂₆)[Cu(NH₂CH₂CH₂NH₂)(H₂O)₂]}·4H₂O (2), have been synthesized in aqueous solution and characterized by IR, UV–vis, single-crystal X-ray diffraction, thermal gravimetric, elemental analysis, and magnetic analysis. Compound 1 is a crown-shaped ring consisted of six edge-sharing MoO₆ octahedra linked to a central {VO₄} unit. The MoO₆ octahedra are in pairs connected with the carboxylato ligands from three acetic acid molecules. Compound 1 is the first example of a molybdovanadate coordinated by acetic acid molecules. In addition, multipoint hydrogen-bonding interactions exist in 1, which bridge the crown-shaped [Mo₆VO₂₂ (CH₃COO)₃]⁶⁻ clusters and the protonated ethylenediamine molecules into three-dimensional (3D) networks. The structural feature of compound 2 is the formation of one-dimensional (1D) zip-zag chain in which [Mo₆V₂O₂₆]⁶⁻ clusters are covalently bonded to copper coordination groups through the terminal oxygen of the {VO₄} tetrahedron. The magnetic investigation on compound 2 demonstrates the possible occurrence of antiferromagnetic interactions by intermolecular linkage.     

Synthesis,crystal structure,and magnetic properties of a salt containing [Cu2Cl7]3− and 4-nitrobenzyl-4′-dimethylaminopyridinium

A new salt, [NO₂BzDMAP]₃[Cu₂Cl₇]?·?H₂O (1), has been synthesized, where [NO₂BzDMAP]⁺ is 1-(4′-nitrobenzyl)-4-dimethylaminopyridinium. Herein, the synthesis, spectral and structural characterization, and magnetic behavior of 1 are reported. It is orthorhombic, with space group Pca2₁, and a?=?26.639(2)?Å, b?=?9.638(1)?Å, and c?=?20.011(2)?Å with V?=?5137.5(7)?ų for Z?=?4. The anion shows a chloride-bridged binuclear structure with Cu?···?Cu distance of 3.872?Å; the two Cu(II) ions have a tetrahedral geometry. The cations stack through p?···?π and π?···?π interactions, and a complicated hydrogen-bonding network structure is formed through C–H?···?Cl and C–H?···?O hydrogen bonds. The variable temperature magnetic susceptibility measurements reveal that 1 exhibits strong antiferromagnetic interaction with J?=??193.0?cm^?1.     

Synthesis,X-ray crystal structure and thermal decomposition of two peroxovanadium complexes with coordinated ammonia molecules: [{VO(O2)2(NH3)}2{μ-Cu(NH3)4}] and [Zn(NH3)4][VO(O2)2(NH3)]2

The compounds [{VO(O₂)₂(NH₃)}₂{μ-Cu(NH₃)₄}] (1) and [Zn(NH₃)₄][VO(O₂)₂(NH₃)]₂ (2) were prepared and characterized by elemental analysis and infrared spectra. The single crystal X-ray study revealed that the structure of 1 consists of trinuclear complex molecules [(NH₃)OV(O₂)₂{μ-Cu(NH₃)₄}(O₂)₂VO(NH₃)] with a rare heterobimetalic peroxo bridge: copper(II)–peroxo ligand–vanadium(V). The structure of 2 is composed of tetraamminezinc(II) cations and ammineoxodiperoxovanadate(V) anions. In course of thermal decomposition of 1 performed up to 620 °C, the following intermediate products: [Cu(NH₃)₂(VO₃)₂], and subsequently a mixture of V₂O₅ with monoclinic β-Cu₂V₂O₇, were gradually formed. The final product of decomposition is Cu(VO₃)₂. The thermal decomposition of 2 is a two-step process. In the first stage, [Zn(NH₃)₃(VO₃)₂] as supposed intermediate was formed, which transformed at higher temperatures by release of ammonia molecules to the monoclinic modification of Zn(VO₃)₂.     

One-dimensional heterobimetallic cyanide-bridged Fe(III)–Mn(II) complex: Synthesis,crystal structure,and magnetic properties

A new cyanide-bridged heterobimetallic Fe(III)–Mn(II) complex {[MnL][FebpdBrb]} [FebpdBrb]_n· 2nH₂O has been synthesized by using pyridinecarboxamide trans-dicyanideiron as the building block. The X-ray diffraction analysis has revealed the one-dimensional infinite structure of the complex consisting of the alternating [Mn(L)]²⁺ and [Fe(bpdBrb)(CN)₂]^– units forming a cyanide-bridged cationic polymeric chain, with [Fe(bpdBrb)(CN)₂]^– as the free anions. The antiferromagnetic coupling between the neighboring Fe(III) and Mn(II) ions through the bridging cyanide group has been revealed. The magnetic coupling constant has been determined as of J =–3.17 cm^–1.     

RERhZn (RE = Y,Sm, Gd–Lu) compounds with TiNiSi type structure – Synthesis and magnetic properties

The TiNiSi type intermetallic compounds RERhZn (RE = Y, Sm, Gd–Lu) were synthesized by induction melting of the elements in sealed tantalum ampoules. They were characterized by X-ray powder diffraction. Five structures were refined from single crystal X-ray diffractometer data: Pnma, Z = 4, a = 699.7(2), b = 405.6(2), c = 816.9(2) pm, wR2 = 0.038, 628 F² values for SmRhZn, a = 696.1(2), b = 405.6(1), c = 811.9(3) pm, wR2 = 0.028, 886 F² values for GdRhZn, a = 692.8(1), b = 403.0(1), c = 809.5(2) pm, wR2 = 0.039, 562 F² values, for TbRhZn, a = 690.6(3), b = 401.50(9), c = 808.2(2) pm, wR2 = 0.036, 763 F² values, for DyRhZn, and a = 688.6(5), b = 399.6(4), c = 808.3(7) pm, wR2 = 0.048, 546 F² values for HoRhZn with 20 variables for each refinement. The rhodium atoms have coordination number 9 (5 RE + 4 Zn atoms) in the form of a tricapped trigonal prism. Together the rhodium and zinc atoms build up three-dimensional [RhZn] networks with short Rh–Zn (263–269 pm in GdRhZn) and Zn–Zn (296 pm in GdRhZn) distances. The gadolinium atoms bind to the [RhZn] network by Gd–Rh bonds (292–294 pm). Magnetic susceptibility measurements show Pauli paramagnetism for YRhZn and van Vleck paramagnetism for SmRhZn. The remaining RERhZn compounds are Curie–Weiss paramagnets which show magnetic ordering at low temperatures.     

Synthesis, crystal growth and structure of Mg containing β-rhombohedral boron: MgB17.4

For the first time, single crystals of Mg containing β-rhombohedral boron MgB_17.4 were synthesised from the elements in a Mg/Cu melt at 1600 °C. The crystal structure determined by the refinement of single crystal data (space group R-3m, , , 890 reflections, 123 variables, R₁(F)=0.049, wR₂(I)=0.122) improves and modifies the former structure model derived from earlier investigations on powder samples. Mg is located on four different positions with partial occupation. While the occupation of the sites D (53.3%), E (91%) and F (7.2%) is already known from other boron-rich borides related to β-rhombohedral boron, the occupation of the fourth position (18h, 6.7%) is observed for the first time. Two boron positions show partial occupation. The summation reveals the composition MgB_17.4 and Mg_5.85B_101.9, respectively, confirmed by WDX measurements. The single crystals of MgB_17.4 show the highest Mg content ever found. Preliminary measurements indicate no superconductivity.     

Synthesis, characterization and catalytic performance of a novel magnetic SO42?-Y2O3-Fe3O4-ZrO2 solid acid catalyst

A novel magnetic SO₄ ²⁻-Y₂O₃-Fe₃O₄-ZrO₂ solid acid catalyst was prepared by the co-precipitation method. The results revealed that the introduction of Y₂O₃ improved markedly the thermal stability of tetragonal zirconia. The catalyst exhibited high catalytic activity and stability in cyclohexanone condensation.     

Synthesis,structure, magnetic properties and kinetics of formation of a cluster containing a {Cu3(μ3-OH)} core supported by a triazole-based ligand

The trinuclear copper complex, [Cu₃(μ₃-OH)(CTMB)₃(NO₃)₂(CH₃CN)₂]·5CH₃CN·H₂O (1) {CTMB = cyclohexotriazole-3-(4-methoxybenzamide)}, has been prepared by mixing Cu(NO₃)₂·2.5H₂O and CHMBH {CHMBH = N,N′-cyclohexane-1,2-diylidene-bis(4-methoxybenzoylhydrazide)} in acetonitrile under ambient conditions. Compound 1 was characterized by IR and UV–visible spectroscopies as well as elemental analyses. X-ray crystallography shows that the cluster contains a {Cu₃(μ₃-OH)} core supported by three triazole-based Schiff base ligands. Each Cu is bound to the 2-N of one triazole ring and the 1-N of another. However, the coordination sphere of each Cu is different, one is five-coordinate and the other two are six-coordinate and bridged by a NO₃ group. The six-coordinate sites are different, one has a terminal NO₃ and the other a MeCN ligand. Magnetic measurements revealed the presence of isotropic and antisymmetric exchange between the copper(II) centers. The data were analyzed using the Hamiltonian containing isotropic exchange for an isosceles triangle together with antisymmetric exchange: H = –J₁(S₁S₂ + S₂S₃)?J₂S₁S₃ + G[S₁ × S₂ + S₂ × S₃ + S₃ × S₁]. Compound 1 exhibits strong antiferromagnetic coupling with J₁ = ?180 and J₂ = ?118 cm^?1 and antisymmetric exchange with G_z = 15 cm^?1. Stopped flow spectrophotometric studies show that the formation of 1 occurs in three distinct phases and the kinetics of each phase has been determined.     

Synthesis, characterization, and structural study of iron-sulfur core {Cp2Fe2(μ-SEt)2} complexes

The known complexes [Cp₂Fe₂(μ-SEt)₂(MeCN)₂](PF₆)₂ (1) and Cp₂Fe₂(μ-SEt)₂(CN)₂ (2) are prepared to investigate their reactivity. The reaction of complex 2 with equimolar amounts of MeOTf yields a monomethylation product [Cp₂Fe₂(μ-SEt)₂(CN)(CNMe)](OTf) (3). Dimethylation of complex 2 by 2 equiv. MeOTf gives a complex [Cp₂Fe₂(μ-SEt)₂(CNMe)₂](OTf)₂ (4). Complex 1 containing two labile MeCN ligands reacts with several bidentate phosphine ligands, such as dppm, dppa, and dppf, to afford complexes [Cp₂Fe₂(μ-SEt)₂(dppm)](PF₆)₂ (5), [Cp₂Fe₂(μ-SEt)₂(dppa)](PF₆)₂ (6), and [Cp₂Fe₂(μ-SEt)₂(dppf)](PF₆)₂ (7), respectively. The spectroscopic, electrochemical, and reactivity studies of iron-sulfur core complexes are performed. The structures of complexes 1-7 were confirmed by X-ray crystallography.