Synthesis and Some Transformations of Complex Salts of Bis-o-dicarbollyliron(II), -cobalt(II), and -nickel(II)

The complex salts [(o-C2B9H11)2M³⁺]₂M'²⁺·4bipy, where M = Fe, Co, or Ni, M' = Fe, Co, Ni, Cu, Mn (M M'), and bipy is 2,2'-bipyridyl, were synthesized. The salts with M = Ni decompose to give 3-(2,2'-bipyridyl)-3,1,2-nickelacarborane, when refluxed in alcohol, and to give 2-(2,2'-bipyridyl)-2,1,7-nickel acarborane, when refluxed in dodecane (216°C).     

“From Heteronuclear Complex to Composite Oxide” Approach in the Synthesis of Nanosized Ferrites MIIFeIII 2O4 (M = Mn,Co, Ni) with Spinel Structure and Their Catalytic Properties

A study was carried out on the preparation of ferrites M^IIFe₂O₄ (M^II = Mn, Co, Ni) by the thermal decomposition of the corresponding ₃-oxoacetates [Fe₂M^IIO(CH₃COO)₆(H₂O)₃]·2H₂O. Nanocrystallites of M^IIFe₂O₄ were formed under mild conditions at 300-400 °C in this reaction. An increase in the temperature leads to an increase in particle size. Nickel ferrite showed high catalytic activity in the reduction of nitrogen oxides (NO _x ) by hydrocarbons.     

Structure and Magnetochemical Properties of [MII(1,10-C12H8N2)3]2+ (M = Mn, Ni, Cu) Cation Salts with ortho-Carboranes(12)

A magnetochemical study has been performed on a series of [M^II(1,10–C₁₂H₈N₂)₃]²⁺ (M^II = Mn, Ni, Cu) cation salts with [B₉C₂H₁₂]^– and [M^III(B₉C₂H₁₁)₂ ]^– (M^III = Co, Ni) ortho-carboranes(12) in the temperature range of 2 K to 300 K. X-ray diffraction (XRD) and X-ray phase analysis (XRPA) data are given and discussed for these compounds. The complexes contain paramagnetic centers of different origin and aromatic fragments of two types in the structures. The results are represented by the temperature (T) dependences of the inverse molar paramagnetic susceptibility (^–1) and effective magnetic moments (_ef) and by Curie–Weiss equations. For two salts with Mn(II), ferromagnetic interactions near T=20 K have been detected, which is a new phenomenon in borane chemistry.     

Strukturelle Charakterisierung der Dicyanamid-Komplexe von Kupfer(II), Nickel(II) bzw. Kobalt(II) mit Aminopyridinen

Summary New dicyanamide complexes of the typeM[N(CN)₂]₂ L ₂ (M=Cu or Ni;L=2-, 3-, 4-aminopyridine, 2-amino-5-nitropyridine) and Co[N(CN)₂]₂ (2-amino-5-nitropyridine)₂ were prepared and studied by spectroscopic methods as well as by room-temperature magnetic moments. The results show that the Cu(II) complexes have elongated pseudooctahedral structures while the Ni(II) and Co(II) complexes are octahedral. In most cases the N(CN)₂ groups are in bridging function and through their cyanide nitrogens, or-more rarely-amide and cyanide nitrogens connect the basic structure units into polymeric conglomerates. In the Cu(II) systems exchange coupling is seen from the _eff value or ESR spectrum.

Professor Viktor Gutmann zum 70. Geburtstag gewidmet     

Metal‐Organic Niccolite: Synthesis,Structures, Phase Transition,and Magnetic Properties of [CH3NH2(CH2)2NH2CH3][M2(HCOO)6] (M=divalent Mn,Fe, Co,Ni, Cu and Zn)

We report the synthesis, crystal structures, thermal and magnetic characterizations of a family of metal‐organic frameworks adopting the niccolite (NiAs) structure, [dmenH₂²⁺][M₂(HCOO)₆²⁻] (dmen=N,N′‐dimethylethylenediamine; M=divalent Mn, 1Mn ; Fe, 2Fe ; Co, 3Co ; Ni, 4Ni ; Cu, 5Cu ; and Zn, 6Zn ). The compounds could be synthesized by either a diffusion method or directly mixing reactants in methanol or methanol–water mixed solvents. The five members, 1Mn , 2Fe , 3Co , 4Ni , and 6Zn are isostructural and crystallize in the trigonal space group P 1c, while 5Cu crystallizes in C2/c. In the structures, the octahedrally coordinated metal ions are connected by anti–anti formate bridges, thus forming the anionic NiAs‐type frameworks of [M₂(HCOO)₆²⁻], with dmenH₂²⁺ located in the cavities of the frameworks. Owing to the Jahn–Teller effect of the Cu²⁺ ion, the 3D framework of 5Cu consists of zigzag Cu‐formate chains with Cu OCHO Cu connections through short basal Cu O bonds, further linked by the long axial Cu O bonds. 6Zn exhibits a phase transition probably as a result of the order–disorder transition of the dmenH₂²⁺ cation around 300 K, confirmed by differential scanning calorimetry and single crystal X‐ray diffraction patterns under different temperatures. Magnetic investigation reveals that the four magnetic members, 1Mn , 2Fe , 3Co , and 4Ni , display spin‐canted antiferromagnetism, with a Néel temperature of 8.6 K, 19.8 K, 16.4 K, and 33.7 K, respectively. The Mn, Fe, and Ni members show spin‐flop transitions below 50 kOe. 2Fe possesses a large hysteresis loop with a large coercive field of 10.8 kOe. The Cu member, 5Cu , shows overall antiferromagnetism (both inter‐ and intra‐chains) with low‐dimensional characteristics.     

On the Thermal Decompositions of the Trivalent Trioxalato Complexes of Al, Cr, Mn, Fe and Co

The thermal decompositions of the complexes K₃[M(ox)₃]3H₂O(M=Al, Cr, Mn, Fe, Co; ox=C₂O₄^2–) were studied. Dehydration of the complexes occurs up to 200°C, this being a three-step process for M=Al, Cr, Mn and Co, and a two-step process for M=Fe. Decomposition of the dehydrated complexes proceeds in several steps. For M=Al, Cr and Fe, the decomposition takes place with the evolution of CO, whereas for M=Mn and Co the decomposition of the oxalate ligand yields solid C besides CO. The temperature of CO liberation decreases in the series Cr<Al<Co<Mn<Fe. For M=transition metal, this trend can be explained by the fact that the strength of the C—C bond in the oxalate ligand decreases in the series Cr<Co<Mn<Fe.This revised version was published online in November 2005 with corrections to the Cover Date.     

Titanium-based mixed oxides from a series of titanium(IV) citrate complexes

The isostructural hexaaquatransition-metal/titanium citrate complexes (NH₄)₂[M(H₂O)₆][Ti(H₂cit)₃]₂·6H₂O [M(II)=Mn 1, Fe 2, Co 3, Ni 4, Cu 5, and Zn 6] (H₄cit=citric acid), which were synthesized by reacting titanium(IV) citrate with divalent metal salts in the 1.0-3.5 pH range, adopt hydrogen-bonded chain motifs. The crystal structures feature three bidentate citrate anions that chelate to the titanium atom through their negatively charged α-alkoxy and α-carboxy oxygen atoms; the chelation is consistent with the large downfield shifts of ¹³C NMR for carbon atoms for complex 6. The thermal decomposition of the complexes furnishes mixed metal oxides. The main-group magnesium analog when heated at 600 °C yielded MgTi₂O₅ that is of the pseudobrookite type; the particle size is approximately 30 nm.     

Use of ethyl oxamate for syntheses of oxamato(-1) and novel μ-oxamato(-2) complexes

Summary The use of ethyl oxamate for the synthesis of inorganic oxamato complexes is reported. A reaction system leading to the preparation of the novel polymeric -oxamato(-2) complexes [M(oxm)(H₂O)₂] _x (M=Cu, Zn, Cd), [Co(oxm)(H₂O)₂] _x ·0.5xH₂O and [Ni(oxm)(H₂O)₂] _x ·xH₂O is described (H₂ oxm = oxamic acid). Ethyl oxamate can also be used for the preparation of monomeric oxamato(-1) complexes.

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Der Einsatz von Ethyloxamat für die Synthese von Oxamato(-1) und neuen -Oxamato(-2)-Komplexen (Kurze Mitt.)

Zusammenfassung Es wird der Einsatz von Ethyloxamat für die Synthese von anorganischen Oxamato-Komplexen beschrieben. Ein Reaktions-System für die Herstellung von neuen -Oxamato(-2)-Komplexpolymeren: [M(oxm)(H₂O)₂] _x ; (M = Cu, Zn, Cd), [Co(oxm)(H₂O)₂] _x ·0.5xH₂O und [Ni(oxm)(H₂O)₂] _x ·xH₂O, wird vorgestellt. Ethyloxamat kann auch für die Herstellung von monomeren Oxamato(-1)-Komplexen verwendet werden.

     

Maleates of Mn(II), Fe(II), Co(II), and Ni(II) as precursors for synthesis of metal-polymer composites

Comparison was made for the structural, IR spectral, and thermoanalytical characteristics of normal [M₁(H₂O)₂(C₄H₂O₄)](H₂O) (M₁ = Co(II) and Ni(II)) and acid maleates [M₂(H₂O)₄(C₄H₃O₄)₂] (M₂ = Mn(II), Fe(II), Co(II) and Ni(II)). Only structures of acid maleates contain intramolecular asymmetric hydrogen bond whose asymmetry increases in the series of transition metal salts. Thermal decomposition of Co(II), Ni(II) normal maleates, and Mn(II), Fe(II), Co(II), Ni(II) acid maleates proceeds in three stages. Onset decomposition temperatures for the first and second stages decreases in the series of normal maleates Co(II) ≥ Ni(II) and increases in the series of acid maleates Fe(II) < Co(II) < Ni(II) ≈ Mn(II). Onset temperature of the third stage decreases in the series of both normal maleates Co(II) > Ni(II) and acid maleates Mn(II) > Fe(II) > Co(II) > Ni(II).     

Synthesis, structure and physical properties of Ru ferrites: BaMRu5O11 (M=Li and Cu) and BaM′2Ru4O11 (M′=Mn, Fe and Co)

The synthesis, structure, and physical properties of five R-type Ru ferrites with chemical formula BaMRu₅O₁₁ (M=Li and Cu) and BaM′₂Ru₄O₁₁ (M′=Mn, Fe and Co) are reported. All the ferrites crystallize in space group P6₃/mmc and consist of layers of edge sharing octahedra interconnected by pairs of face sharing octahedra and isolated trigonal bipyramids. For M=Li and Cu, the ferrites are paramagnetic metals with the M atoms found on the trigonal bipyramid sites exclusively. For M′=Mn, Fe and Co, the ferrites are soft ferromagnetic metals. For M′=Mn, the Mn atoms are mixed randomly with Ru atoms on different sites. The magnetic structure for BaMn₂Ru₄O₁₁ is reported.     

Spectral and Thermal Studies of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) Complexes with 3-methylglutaric Acid

Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 3-methylglutarates were prepared as solids with general formula MC₆ H₈ O₄ ×n H₂ O, where n =0–8. Their solubilities in water at 293 K were determined (7.0×10⁻² −4.2×10⁻³ mol dm⁻³ ). The IR spectra were recorded and thermal decomposition in air was investigated. The IR spectra suggest that the carboxylate groups are mono- or bidentate. During heating the hydrated complexes lose some water molecules in one (Mn, Co, Ni, Cu) or two steps (Cd) and then mono- (Cu) or dihydrates (Mn, Co, Ni) decompose to oxides directly (Mn, Cu, Co) or with intermediate formation of free metals (Co, Ni). Anhydrous Zn(II) complex decomposes directly to the oxide ZnO. This revised version was published online in July 2006 with corrections to the Cover Date.     

Immobilization of (dd)heteronuclear hexacyanoferrates(II) in a gelatin matrix

The data concerning a possibility of the synthesis (dd)heteronuclear hexacyanoferrates(II) with (M¹)^II and (M²)^II ions (M¹, M² = Mn, Co, Ni, Cu, Zn, or Cd) due to the contact of M¹ ₂[Fe(CN)₆] immobilized in the gelatin matrix with aqueous solutions of M²Cl₂ chlorides, were systematized and generalized. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 8–17, January, 2008.     

Vibrational Spectroscopic Study of [1,2-bis(4-pyridyl)ethane]metal(II) Tetracyanonickelate(II). 2 m-Xylene Clathrates

Four new Hofmann-type clathrates of the form M(bpa)₂Ni(CN)_4· 2m-xylene (M = Mn , Fe , Co and Ni; bpa = 1,2-bis(4-pyridyl)ethane) have been synthesized and characterized by vibrational spectroscopy. The M(bpa)₂Ni(CN)₄ (M = Fe and Co) host structure is similar to the classical Hofmann-type host framework composed of layers of a two dimensional catena-metal tetra--cyanonickelate(II) network, but in M(bpa)₂Ni(CN)₄ (M = Mn and Ni), the Ni(CN)₄ moiety behaves as a bidentate –[NC-Ni(CN)₂-CN–]– unit in the host framework.     

New Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with 3,3-dimethylglutaric Acid

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)3,3-dimethylglutarates were investigated and their quantitative composition, solubility in water at 293 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with general formula MC₇H₁₀O₄⋅nH₂O (n=0−2) were recorded and their thermal decomposition in air were studied. During heating the hydrated complexes of Mn(II),Co(II), Ni(II) and Cu(II) are dehydrated in one step and next all the anhydrous complexes decompose to oxides directly (Mn, Co, Zn) or with intermediate formation free metal (Ni,Cu) or oxocarbonates (Cd). The carboxylate groups in the complexes studied are bidentate. The magnetic moments for the paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II)attain values 5.62, 5.25, 2.91 and 1.41 M.B., respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Magnetische Eigenschaften der Verbindungen BaMF4 und Pb2 MF6 (M=Mn,Fe, Co,Ni, Cu,Zn)

Zusammenfassung In den beiden untersuchten Doppelfluorid-Serien, BaMF₄ und Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn), zeigen die Verbindungen des Cu und des Zn ein anderes Verhalten als die übrigen. Die Zn-Verbindungen sind diamagnetisch, die Cu-Verbindungen paramagnetisch. Pb₂CuF₆ befolgt dasCuriesche Gesetz, während BaCuF₄ eineCurie-Weiss-Abweichung unterhalb 212 K aufweist.Im untersuchten Temperaturbereich zeigt sich für alle anderen Verbindungen, mit Ausnahme von Pb₂FeF₆, Antiferromagnetismus.

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Magnetic properties of the compounds BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn)

Two series of double fluorides, BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn) have been studied, the compounds of Cu and Zn differing in behaviour from the others. The Zn componds are diamagnetic, the Cu compounds paramagnetic. Pb₂CuF₆ conforms toCurie's law while BaCuF₄ exhibits aCurie-Weiss deviation below 212° K.With the exception of Pb₂FeF₆, all the other compounds show antiferromagnetism in the studied temperature range.

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Mit 5 Abbildungen

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Herrn Prof. Dr.Hans Nowotny ergebenst gewidmet.     

Coordination compounds of heterocyclic azo derivatives. III. Co(II), Ni(II) and Cu(II) complexes of some arylazo-4,5-diphenylimidazole derivatives

The 3d transition metalion [Co(II), Ni(II) and Cu(II)] complexes of some 4,5-diphenylimidazole azo derivatives have been isolated and characterized by chemical analysis, conductance, electronic and IR spectra. These dyes are characterized by a high tendency towards complex formation with the neutral molecules coordinated to the metal ion as bidentate ligands. The molecular formula of the 1:1 and 1:2 complexes are suggested to be [MLX ₂(H₂O)₂] and [ML ₂ X ₂] or [ML ₂ X ₂]·2H₂O respectively, whereX=Cl^– or NO₃. the different bands observed in the visible spectra of methanolic solutions of the complexes have been assigned to the possible electronic transition type (L MCT and d-d). It is suggested that the complexes studied have a distorted octahedral geometry.

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Koordinatsverbindungen von heterocyclischen Azo-Derivaten, 3. Mitt.: Co(II)-, Ni(II)- und Cu(II)-Komplexe einiger Arylazo-4,5-diphenylimidazol-Derivate

Zusammenfassung Es wurden einige Komplexe von 4,5-Diphenylimidazol-azo-Derivaten mit den 3 d-Übergangsmetallen Co(II), Ni(II) und Cu(II) isoliert und mittels chemischer Analyse, Leitfähigkeitsmessungen und den Elektronen- bzw. IR-Spektren charakterisiert. Diese Farbstoffe zeigen eine sehr starke Tendenz zur Komplexbildung, wobei die neutralen Moleküle als zweizähnige Liganden an das Metallion koordinieren. Die Formeln für die 1:1- und 1:2-Komplexe werden mit [MLX ₂(H₂O)₂] und [ML ₂ X ₂] bzw. [ML ₂ X ₂]·2H₂O vorgeschlagen (X=Cl^– oder NO ₃ ^– ). Die verschiedenen Absorptionsbanden in den VIS-Spektren in methanolischer Lösung werden den möglichen e-Übergängen (L MCT und d-d) zugeordnet. Für die Komplexe werden verzerrte oktaedrische Geometrien vorgeschlagen.

     

Catalytic properties of ferrites in oxidation reactions

Catalytic activities of ferrites MFe₂O₄ (M = Cu, Co, Ni, Mg, and Zn) and M¹ _0.5M² _{0 .5}Fe₂O₄ (M¹ = CU; M² = Co, Zn, and Mg) in oxidation of CO and ethylbenzene were investigated, and their dependences on the cation nature were established. Higher activities were observed for catalysts containing ions with variable valence (Cu, Co, and Ni). A correlation between catalytic and adsorption properties of ferrites was found.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 49–52, January, 1996.     

Electronic structure of transition-metal complexes. I. Parametrization for CNDO/2 method

A new parameterization for the first transition metal has been proposed in the framework of CNDO /2 method. We carried out CNDO /2 calculation of hexamine complexes [M(NH₃)₆]²⁺ and hexa-aquo complexes [M(OH₂)₆]²⁺ in the high spin state where M = Mn, Fe, Co, Ni, and Cu, using new parameters. It is shown that the calculated order of binding energy is Mn? L < Fe? L < Co? L < Ni? L ≈ Cu? L (where L means the ligand), and is in good agreement with experiment. We discussed how the orbital nodes affect the nature of bonding between metal and ligand.     

The crystal and molecular structure of bis(thiourea)iron (11) thiocyanate

Summary The crystal structure of bis(thiourea)iron(II) thiocyanate, Fe[SC(NH₂)₂]₂(NCS)₂, has been determined and refined by three-dimensional x-ray analysis. The complex crystallizes in the triclinic system, space group P –1, witha = 10.114(6),b = 7.662(8),c = 3.897(10) Å, = 105.0(2)°, = 81.8(3)°, = 96.4(3)° andz = 1. It is isostructural with M(tu)₂(NCS)₂, where M = Mn, Co or Ni and to = thiourea. The iron atom is located on a centre of symmetry and is coordinated to four planar sulfur atoms of the thiourea ligands (Fe-S 2.61 and 2.65 Å) and two nitrogen atoms of the thiocyanate groups (Fe-N 2.05 Å) in a distorted octahedral way. These octahedra are linked in chains with each thionilic sulfur atom shared by two adjacent iron atoms; magnetic measurements, Mössbauer and spectroscopic data are consistent with this polymeric structure.     

Phase formation in the systems Ag2MoO4-MO-MoO3 (M=Ca, Sr, Ba, Pb, Cd, Ni, Co, Mn) and crystal structures of Ag2M2(MoO4)3 (M=Co, Mn)

Phase equilibria in the systems Ag₂MoO₄-MMoO₄ (M=Ca, Sr, Ba, Pb, Ni, Co, Mn) and subsolidus phase relations in the systems Ag₂MoO₄-MO-MoO₃ (M=Ca, Pb, Cd, Mn, Co, Ni) were investigated using XRD and thermal analysis. The systems Ag₂MoO₄-MMoO₄ (M=Ca, Sr, Ba, Pb, Ni) belong to the simple eutectic type whereas in the systems Ag₂MoO₄-MMoO₄ (M=Co, Mn) incongruently melting Ag₂M₂(MoO₄)₃ (M=Co, Mn) were formed. In the ternary oxide systems studied no other compounds were found. Low-temperature LT-Ag₂Mn₂(MoO₄)₃ reversibly converts into the high-temperature form of a similar structure at 450-500°C. The single crystals of Ag₂Co₂(MoO₄)₃ and LT-Ag₂Mn₂(MoO₄)₃ were grown and their structures determined (space group , Z=2; lattice parameters are a=6.989(1) Å, b=8.738(2) Å, c=10.295(2) Å, α=107.67(2)°, β=105.28(2)°, γ=103.87(2)° and a=7.093(1) Å, b=8.878(2) Å, c=10.415(2) Å, α=106.86(2)°, β=105.84(2)°, γ=103.77(2)°, respectively) and refined to R(F)=0.0313 and 0.0368, respectively. The both compounds are isotypical to Ag₂Zn₂(MoO₄)₃ and contain mixed frameworks of MoO₄ tetrahedra and pairs of M²⁺O₆ octahedra sharing common edges. The Ag⁺ ions are disordered and located in the voids forming infinite channels running along the a direction. The peculiarities of the silver disorder in the structures of Ag₂M₂(MoO₄)₃ (M=Zn, Mg, Co, Mn) are discussed as well as their relations with analogous sodium-containing compounds of the structural family of Na₂Mg₅(MoO₄)₆. The phase transitions in Ag₂M₂(MoO₄)₃ (M=Mg, Mn) of distortive or order-disorder type are suggested to have superionic character.