Structure and magnetic and electric properties of bismuth niobates doped with d elements: IV. Magnetic behavior of chromium-containing solid solutions with the structure of bismuth niobate, Bi5Nb3O15

The magnetic susceptibility and electrophysical properties of chromium-containing Bi₅Nb_3−3x · Cr_3x O_15−δ solid solutions with the perovskite-like structure were studied. Parameters of exchange interactions in the dimeric clusters of chromium atoms and also the distribution of chromium monomers and dimers in the solid solutions were calculated. Original Russian Text ? N.A. Zhuk, I.V. Piir, A.L. Pimenov, N.V. Chezhina, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 6, pp. 898–904. For communication III, see [1].     

Structure and magnetic and electric properties of bismuth niobates doped with <Emphasis Type="Italic">d</Emphasis>-elements: III. Magnetic and electric properties of copper-containing solid solutions of bismuth orthoniobate

Magnetic susceptibility and electrophysical properties of copper-containing solid solutions of the low-temperature modification of bismuth orthoniobate were studied. Parameters of exchange interactions in dimeric copper clusters and distribution of monomers and dimers in the solutions were calculated. The exchange parameter of antiferromagnetic interactions in dimeric copper clusters was found to be 170 cm⁻¹. Original Russian Text N.A. Zhuk, I.V. Piir, N.V. Chezhina, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 2, pp. 240–245. For communication II, see [1].     

Structure, magnetic, and electric properties of bismuth niobates doped with d -Elements: VI. Magnetic behavior of Bi3Nb3?3 x Ni3 x O15?δ solid solutions

Magnetic susceptibility of nickel-containing solid solutions with layered perovskite-like structure of bismuth niobate, Bi₅Nb₃O₁₅, was studied. High-spin nickel atoms, Ni(III), were present at low concentrations of the solid solutions. The formation of exchange-bonded aggregates (dimers) of nickel(II) atoms with antiferromagnetic type of exchange was found in the solid solutions. The parameters of exchange interactions in the dimer clusters and the distribution of monomers and dimers of nickel atoms were calculated as a function of the solid solution concentration. Original Russian Text ? N.A. Zhuk, I.V. Piir, N.V. Chezhina, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 3, pp. 393–399. For communication V, see [1].     

Electronic structure and reactivity of PO 43? , P2O 74? phosphate and SO 42? , S2O 72? sulfate anions

Group-theoretical analysis and molecular orbital methods were used to obtain (in analytical form) the electronic structure and reactivity of the PO ₄ ³⁻ , SO ₄ ²⁻ and P₂O ₇ ⁴⁻ , S₂O ₇ ²⁻ anions. The reactivity of the anions is dictated by the availability of lone electron pairs on the top quasidegenerate MOs in the form of linear combinations of group orbitals from atomic orbitals (AOs) of peripheral oxygen atoms for PO ₄ ³⁻ , SO ₄ ²⁻ and the central (bridging) atom for P₂O ₇ ⁴⁻ , S₂O ₇ ²⁻ . These electron pairs are responsible for the donor-acceptor interactions during complexation, clustering, and other (addition, substitution, etc.) reactions. Original Russian Text Copyright ? 2005 V. A. Zasukha, A. P. Shpak, V. V. Trachevskii, and E. V. Urubkova __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 3, pp. 405–415, May–June, 2005.     

Structure,magnetic, and electrical properties of bismuth niobates doped with <Emphasis Type="Italic">d</Emphasis>-elements: XVI. Magnetic properties of manganese-containing solid solutions of bismuth orthoniobate BiNiO<Subscript>4</Subscript>

Magnetic susceptibility and ESR properties of manganese-containing solid solutions of bismuth orthoniobate BiNb_1–x Mn_xO_4–δ have been studied. Mn(II), Mn(III), and Mn(IV) atoms as well as their dimers exhibiting antiferro- and ferromagnetic types of exchange have been found in the solid solutions. Parameters of the exchange interactions in the clusters and the distribution of monomers and dimers of manganese atoms in the solid solutions have been calculated as functions of the paramagnetic atom fraction.     

Theoretical study of the structure and stability of the dimers of heme analogues (MC34H32N4O4)2 and their ions (MC34H32N4O4) 2+ with 3 d -metal atoms M

The electronic and geometric structures and the energetic characteristics of a series of monomeric MC₃₄H₃₂N₄O ₄ ^0,+ and dimeric (MC₃₄H₃₂N₄O₄) ₂ ^0,+ molecules, heme analogues and their positively charged ions with 3d-metal atoms M = Ti, V, Cr, and Mn, have been calculated by the density functional theory B3LYP method with the Gen−1 = 6−31G^*(Fe) + 6−31G(C, H, N, O) and Gen−2 = 6−311+G^*(Fe) + 6−31G^*(C, H, N, O) basis sets. The computation results are compared with the analogous calculated data on the heme dimers (heme) ₂ ^0,+ . Computations show that for the (MC₃₄H₃₂N₄O₄) ₂ ^0,+ dimers, high-spin states are preferable. In these dimers, the rings are linked with each other by a pair of M-carbonyl bridges M⋯O_b=C(OH) and a pair of hydrogen bridges OH_b⋯N. The calculated energies of dissociation D of the dimers into monomers point to a rather high stability of the dimers at the beginning of the 3d series (D ∼ 2.3–3.6 eV for M = Ti, V), which decreases rapidly as the atomic number of M increases (D ∼ 0.5 eV for M = Cr and ∼0.4 eV for (heme)₂). The positive ions (MC₃₄H₃₂N₄O₄) ₂ ⁺ are ∼0.8–1.0 eV are more stable to dissociation than their neutral congeners (MC₃₄H₃₂N₄O₄)₂. The trends in the behavior of the energetic and structural characteristics of the dimers (distances R(M—N), displacements of M atoms from the porphyrin ring plane, parameters of the carbonyl and hydrogen bridges, character of ring distortions, etc.), as well as in the spin density distribution between the metal atoms and the rings in the monomers MC₃₄H₃₂N₄O₄ and dimers (MC₃₄H₃₂N₄O₄)₂ caused by their ionization and going along the 3d series, are examined. In the mixed dimer (FeC₃₄H₃₂N₄O₄)(VC₃₄H₃₂N₄O₄), the rings are linked by only one strong carbonyl bridge V⋯O_b=C(OH), with some contribution made by the neighboring hydrogen bridge. The dissociation energy of this mixed dimer into monomers is close to a half of the dissociation energy of the “symmetric” dimer (VC₃₄H₃₂N₄O₄)₂. Original Russian Text ? O.P. Charkin, N.M. Klimenko, D.O. Charkin, S.H. Lin, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 8, pp. 1332–1346.     

State of atoms of the transition group elements in dilute solid solutions based on LiMO2 (M = Sc, Ga, Al): II. Magnetic characteristics of nickel atoms in LiNi x Sc1 ? x O2 solid solutions

The state of nickel atoms in LiNi _x Sc_{1 − x} O₂ solid solutions was studied. The anomalous magnetic characteristics can be accounted for only by the presence of dilution-resistant clusters containing Ni(III) in two states: high- and low-spin. Original Russian Text ? A.A. Selyutin, N.P. Bobrysheva, N.V. Chezhina, A.V. Shchukarev, A.O. Kozin, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 10, pp. 1608–1612. For communication I, see [1].     

Ionic mobility, ionic transport, and charge transfer mechanism in solid solutions (1 ? x )PbF2- x MF n by the NMR and impedance spectroscopy data

The internal mobility and ionic conduction of solid solutions in systems PbF₂-MF₂ and PbF₂-MF₃ are studied by the NMR (¹⁹F, ²⁷Al, ²⁰⁷Pb) and impedance spectroscopy methods. Factors that define the form of ionic movements and their energy characteristics in the temperature region 150 to 550 K are considered and analyzed. Temperature shifts of the frequency range that defines the ionic conduction of solid solutions are discovered on the basis of impedance spectroscopy data and explained. It is established that the high ionic conductance in lead difluoride doped with fluorides of metals of Groups II and III is caused by the diffusion of fluoride ions. The large values of specific conductance (10⁻⁴ to 10⁻³ S cm⁻¹) at a relatively low activation energy (less than 0.6 eV) allow one to consider the solid solutions studied in the role of a basis for the obtaining of new fluoride materials with high ionic conductance. Original Russian Text ? V.Ya. Kavun, A.B. Slobodyuk, S.L. Sinebryukhov, E.V. Tararako, V.K. Goncharuk, S.V. Gnedenkov, V.I. Sergienko, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 6, pp. 643–656. Based on the report delivered at the 8th International Meeting on Fundamental Problems of Solid-State Ionics, Chernogolovka (Russia), 2006.     

Protonation of the acyclic tetraaza metallocomplex of gold(III) [Au(C9H19N4)]2+ in aqueous solution. Synthesis and crystal and molecular structure of [Au(C9H20N4)](H5O2)(ClO4)4

Protonation equilibrium has been studied for the acyclic gold(III) tetraaza metallocomplex [AuB]²⁺ [B = N, N′-bis(2-aminoethyl)-2,4-pentanediiminato(1−)] in aqueous solution. The synthetic procedure is described. The crystal and molecular structure of the protonated form of the [AuHB](H₅O₂)(ClO₄)₄ complex has been determined. Monoclinic crystals with unit cell dimensions a = 11.964(2) Å, b = 13.789(3) Å, c = 15.496(3) Å, β = 109.00(3)°, V = 2417.1(8) ų, Z = 4, ρcalc = 2.243 g/cm³, space group P2₁/n. The structure is built of nearly planar [Au(C₉H₂₀N₄)]³⁺ complex cations, (H₅O₂)⁺ cations, and [ClO₄]⁻ anions. The gold atom coordinates four nitrogen atoms of the ligand, forming a square plane. The six-membered chelate ring of the ligand is protonated at the central β-carbon atom and contains imine C=N bonds. The oxygen atoms of the perchlorate ions are hydrogen bonded to the (H₅O₂)⁺ dihydroxonium ion and to the nitrogen atoms of the NH₂ groups of the [AuHB]³⁺ cation. Original Russian Text Copyright ? 2005 by V. A. Afanasieva, L. A. Glinskaya, R. F. Klevtsova, and I. V. Mironov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 5, pp. 909–915, September–October, 2005.     

Physicochemical properties of the surface of the (Y,La0.1)Ce x Zr1? x O2?δ( x = 0.1–0.7) and Y0.1Pr0.3Zr0.6O2?δ complex oxide systems

The physicochemical properties of the surface of the Y_0.1Ce _x Zr_1−x O_2−δ, La_0.1Ce _x Zr_1−x O_2−δ (x=0.1–0.7), and Y_0.1Pr_0.3Zr_0.6O_2−δ. complex oxide systems were studied using IR and X-ray photoelectron spectroscopies. An appreciable enrichment of the surface of the solids in rare-earth-metal cations (cerium or praseodymium) during the synthesis was revealed. While cations are uniformly spread over the surface of cerium-zirconium solid solutions, the Y_0.1Pr_0.3Zr_0.6O_2−δ surface is covered by the clusters or even a phase of praseodymia. Reductive treatment in hydrogen with subsequent reoxidation results in the segregation of cerium ions on the Y_0.1Ce_0.3Zr_0.6O_2−δ surface at a temperature as low as 770 K. Original Russian Text ? A.N. Kharlanov, L.N. Ikryannikova, V.V. Lunin, A. Yu. Stakheev, 2007, published in Zhurnal Fizicheskoi Khimii, 2007, Vol. 81, No. 7, pp. 1271–1277.     

XRD and UV-Vis diffuse reflectance analysis of CeO2-ZrO2 solid solutions synthesized by combustion method

A series of ceria-incorporated zirconia (Ce_1−xZr_xO₂,x = 0 to 1) solid solutions were prepared by employing the solution combustion synthesis route. The products were characterized by XRD and UV-Vis-NIR diffuse reflectance spectroscopy. The materials are crystalline in nature and the lattice parameters of the solid solution series follow Vegard’s law. Diffuse reflectance spectra of the solid solutions in the UV region show two intense bands at 250 and 297 nm which are assigned respectively to Ce³⁺ ← O²⁻and Ce⁴⁺ ← O²⁻ charge transfer transitions. The two vibrational bands in 6960 cm⁻¹ and 5168 cm⁻¹ in the NIR region indicate the presence of surface hydroxyl groups on these materials.     

Crystal structure of the reaction product of copper(II) nitrate with α-(3,3-Dimethyl-3,4-dihydro-1-isoquinolyl)hydroxy-iminoacetonitrile [Cu3(μ3-OH)(μ-L)3(NO3)2(H2O)] · 2H2O

The coordination compound [Cu₃(μ₃-OH)(μ-L)₃(NO₃)₂(H₂O)] · 2H₂O (I), where L is the α-(3,3-dimethyl-3,4-dihydro-1-isoquinolyl)hydroxyiminoacetonitrile anion, has been synthesized. The crystal and molecular structure of I was determined by X-ray diffraction (Enraf-Nonius CAD4, MoK _α radiation, graphite monochromator, ω-scan mode, 2θ_max = 49.96°, 7673 unique reflections, a = 12.745(3) ?, b = 13.726(3) ?, c = 28.835(6) ?, β = 93.44(3)°, V = 5035.2(17) ?³, Z = 4, space group P2₁/c). In the trimer complex I, the copper atoms are combined by a bridging hydroxy group. The copper atoms are additionally linked pairswise by three tridentate chelating bridging organic anions coordinated to the Cu(II) atoms by the N and O atoms of the deprotonated oxime group and by the N atom of the dihydroisoquinoline moiety. Original Russian Text ? V.I. Sokol, V.V. Davydov, N. Yu. Merkur’eva, E.I. Polyakova, Yu.V. Shklyaev, V.S. Sergienko, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 10, pp. 1643–1652.     

X-ray photoelectron and voltammetry studies of the charged state of the metal atom in nickel(II) chelate complexes with ligands containing CS 2? and PS 2? groups and in their mixed-ligand complexes

X-ray photoelectron and voltammetry studies of the charged state of the metal atom in nickel(II) chelate complexes with ligands containing CS ₂ ⁻ and PS ₂ ⁻ groups and in heteroligand complexes on their basis were carried out. It is shown that the degree of formal oxidation of the nickel atom in the complexes corresponds to Ni(II). In the case of heteroligand complexes, addition of nitrogen heterocycles causes an increase in the electron density on the atoms of the coordination center. Theoretical data obtained in ab initio quantum chemical model calculations correlate with the experimental results. Original Russian Text Copyright ? 2005 by L. N. Mazalov, S. V. Trubina, I. M. Oglezneva, N. A. Kryuchkova, O. V. Tarasenko, V. L. Varand, T. E. Kokina, and S. V. Larionov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 3, pp. 554–557, May–June, 2005.     

Solubility and Ionic Processes in the Cu X 2? MX ?H2O ( X ?=Cl?, Br?; M +=Li+, Na+, K+, NH4+, Cs+) Systems

Summary.  Solubility isotherms in the CuBr₂−MBr−H₂O (M ⁺ = Li⁺, Na⁺, Cs⁺) systems at 298.15 K were measured. The results together with other available literature data for copper chloride and bromide systems were treated by hydration analysis, and comparative discussion of ionic processes taking place in the respective saturated solutions was performed. Corresponding author. E-mail: jitka@prfdec.natur.cuni.cz Received August 6, 2002; accepted (revised) November 29, 2002 Published online April 3, 2003     

Spacered dinuclear copper(<Emphasis Type="SmallCaps">II</Emphasis>) complexes with acyldihydrazones of aliphatic dicarboxylic acids and 2-hydroxy-5-nitroacetophenone

Dinuclear copper(II) complexes with acyldihydrazones of 2-hydroxy-5-nitroacetophenone (H₄L) of the composition Cu₂(Py)_xL·mEtOH were synthesized and characterized. In these complexes, the coordination polyhedra of the copper atoms are linked to each other by a polymethylene chain of different lengths, from one to five monomer units. The structure of the [Cu₂L·4Mrf] complex (Mrf is morpholine) based on acyldihydrazone of malonic acid was established by X-ray diffraction. The copper(II) atoms in this complex are [4+1]-coordinated and are spaced by 6.94 Å. At room temperature, the signal in the ESR spectra of solutions of the complexes based on acyldihydrazones of malonic, succinic, glutaric, and adipic acids has a seven-line hyperfine structure with the constant of (35.3–38.8)·10⁻⁴ cm⁻¹ (g = 2.109–2.112) due to exchange interactions between unpaired electrons and two equivalent copper nuclei. An increase in the length of the polymethylene chain to five monomer units hinders exchange interactions, and the ESR signal of the complex based on acyldihydrazone of pimelic acid has a four-line hyperfine structure with a _Cu = 72.7·10⁻⁴ cm⁻¹ typical of mononuclear copper(II) complexes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 229–234, February, 2007.     

Solubility and Ionic Processes in the Cu X 2? MX ?H2O ( X ?=Cl?, Br?; M +=Li+, Na+, K+, NH4+, Cs+) Systems

 Solubility isotherms in the CuBr₂−MBr−H₂O (M ⁺ = Li⁺, Na⁺, Cs⁺) systems at 298.15 K were measured. The results together with other available literature data for copper chloride and bromide systems were treated by hydration analysis, and comparative discussion of ionic processes taking place in the respective saturated solutions was performed.     

Synthesis, crystal structure, and spectra of 9(E)-phenanthrene-9,10-dione[(1Z)-3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]hydrazone and its cation-anion complex with copper(I) bromide

The reaction of 1-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline with 9,10-phenanthrenequinone gave (9E)-phenanthrene-9,10-dione[(1Z)-3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]hydrazone (L). The reaction of L with copper(II) bromide gave the complex (LH)[CuBr₂]. The crystal structures of the monohydrate L · H₂O (I) and the isolated complex (LH)[CuBr₂] (II) were determined by X-ray diffraction. The structural units of I are pseudo-centrosymmetric dimers in which the L and water molecules are combined by strong hydrogen bonds. The active H atom is located at the N(1) atom of the isoquinoline fragment of the L molecule. The L molecule occurs in the crystal as the cis, trans isomer with respect to exocyclic C=N bonds at the isoquinoline and phenanthrenequinone fragments, respectively. Complex II has a cation-anion structure. The LH⁺ cation as the cis, cis isomer is protonated at N(2) and stabilized by two intramolecular hydrogen bonds. In the CuBr₂⁻ anion, the copper atom in the oxidation state +1 has a linear coordination, the C-Br bond length is 2.185(4) ± 0.005 ?, and the BrCuBr angle is 179.8(4)°. The main ion-ion interactions in structure II are shortened contacts involving bromine atoms, which combine cations and anions into a three-dimensional framework. Original Russian Text ? V.V. Davydov, V.I. Sokol, N.V. Rychagina, R.V. Linko, M.A. Ryabov, Yu.V. Shklyaev, V.S. Sergienko, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 6, pp. 958–970.     

Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

A novel monomer copper(II) complex [Cu(L)₂(SCN)] · ClO₄ (1) and a tetranuclear cobalt(II) complex [Co₄(L)₄(N₃)₄](OH)₄ · 2H₂O (2)(L = 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine) have been synthesized and structurally characterized. Single crystal X-ray analyses show that the Cu(II) atom is in a distorted trigonal bipyramidal coordinated environment consisting of four N atoms of L and one N atom of SCN⁻ in complex (1), and the monomer is extended to a 1D chain by the weak intermolecular π...π stacking interactions. In the complex (2), four Co(II) atoms are linked by four bridging azido groups in μ-1,1-N₃ (end-on) coordination mode to form a tetranuclear configuration. The fungicidal activity of the title compounds have been studied, and the results show that there are certain activities against several bacteria for the complexes and the ligand. Furthermore, two complexes exhibit blue emission fluoresce in the solid state at room temperature.     

Structure and magnetic properties of the copper(II) complexes with diacyl hydrazides of salicylic acid

The structures and results of the static magnetic susceptibility investigation of the copper(II) binuclear complex with salicylic acid diacyl hydrazide (H₂L), [Cu₂(L)(Py)₄] (I), and the copper(II) trinuclear complex with diacyl dihydrazide of salicylic and glutaric acids (H₆L′), [Cu₃(L′)(Py)₄] · 2Py (II), are described. The exchange antiferromagnetic interactions between the paramagnetic centers with the exchange interaction parameter −2J = 119 cm⁻¹ for dimer I and 14 cm⁻¹ for trinuclear complex II are detected.     

New Bimetallic Ni–Rh Carbonyl Clusters: Synthesis and X-ray Structure of the [Ni7Rh3(CO)18]3?, [Ni3Rh3(CO)13]3? and [NiRh8(CO)19]2? Cluster Anions

The reaction of the [Ni₆(CO)₁₂]²⁻ dianion with [Rh(COD)Cl]₂ (COD = cyclooctadiene) in acetone affords a mixture of bimetallic Ni–Rh clusters, mainly consisting of the new [Ni₇Rh₃(CO)₁₈]³⁻ and [Ni₈Rh(CO)₁₈]³⁻ trianions. A study of the reactivity of [Ni₇Rh₃(CO)₁₈]³⁻ led to isolation of the new [Ni₃Rh₃(CO)₁₃]³⁻ and [NiRh₈(CO)₁₉]²⁻ anions. All these new bimetallic Ni–Rh carbonyl clusters have been isolated in the solid state as tetrasubstituted ammonium salts and have been characterised by elemental analysis, X-ray diffraction studies, ESI-MS and electrochemistry. The unit cell of the [NEt₄]₃[Ni₇Rh₃(CO)₁₈] salt contains two orientationally-disordered ν₂-tetrahedral [Ni₇Rh₃(CO)₁₈]³⁻ trianions with occupancy factors of 0.75 and 0.25. Besides, their inner Ni₃Rh₃ octahedral moieties show two cis sites purely occupied by Rh atoms, two trans sites purely occupied by Ni atoms and the remaining two cis sites are disordered Ni and Rh sites with respective occupancy fraction of 0.5. At difference from the parent [Ni₇Rh₃(CO)₁₈]³⁻, the octahedral [Ni₃Rh₃(CO)₁₃]³⁻ displays an ordered distribution of Ni and Rh atoms in two staggered triangles. The [NiRh₈(CO)₁₉]²⁻ dianion adopts an isomeric metal frame with respect to that of the [PtRh₈(CO)₁₉]²⁻ congener. As a fallout of this work, new high-yield synthesis of the known [Ni₆Rh₃(CO)₁₇]³⁻ and [Ni₆Rh₅(CO)₂₁]³⁻, as well as other currently-investigated bimetallic Ni–Rh clusters have been obtained.