Das erste Alkali-Erdalkali-Oxocuprat(II,III): NaBa2Cu22+Cu3+O6

The first Alkaline Alkaline-Earth Oxocuprate (II, III): NaBa₂Cu₂²⁺Cu³⁺O₆ The compound NaBa₂Cu₃O₆ was prepared by heating of Na₂O₂, BaO₂, Cu₂O in closed Ag-tubes. X-ray single crystal investigations led to orthorhombic symmetry, space group D-Fmmm; a = 8.4229; b = 11.4418; c = 14.4063 Å; Z = 8. Cu²⁺ and Cu³⁺ show square planar polygones of four and Na⁺ trigonal prisms of six O^2?. The two barium point positions show coordination numbers C.N. = 8 and 6 + 4. The crystal structure is discussed.     

Ba2Cu3O5+δ as an intermediate phase during the synthesis of YBa2Cu4O8

We propose a reaction model for the synthesis of YBa₂Cu₄O₈ under normal pressure conditions, which contains 4 partial reaction steps. In a first step bariumnitrate and copperoxide react to Ba₂Cu₃O_5+δ. This substance will be formed for each mixtures Ba:Cu=2∶3...3∶2. The following two partial reaction steps are connected to Ba₂Cu₃O_5+δ, which reacts with Y₂O₃ and CuO to YBa₂Cu₄O₈ or decomposes to BaCuO₂ and CuO. In a last step parts of BaCuO₂ reacts with Y₂O₃ and CuO to YBa₂Cu₄O₈.     

Zur Kristallchemie von Ba3In2Zn5O11. Ein tOxoindat/zinkatsol;zinkat mit Zn10O20- und In4O16-Makropolyedern und erstmals O2− in tetraedrischer Koordination durch Zn2+

On the Crystal Structure of Ba₃In₂Zn₅O₁₁. An Oxoindate/zincatesol;zincate with Zn₁₀O₂₀ and In₄O₁₆ Macropolyhedra with Zn²⁺ in Tetrahedral Coordination by O^2? Ba₃In₂Zn₅O₁₁ was prepared for the first time by a flux technique and investigated by single crystal X-ray work. It crystallizes with cubic symmetry, space group T-F4 3m, a = 13.3588 Å, Z = 8. Zn²⁺ show tetrahedral coordination by O^2?, forming Zn₁₀O₂₀ macropolyhedra. In addition the nZn/Osol;O part of the crystal structure is made up of Zn₁₀O₂₀ parts. Edge connection of four InO₆ octahedra results in In₄O₁₆ groups. The crystal structure will be shown and discussed.     

Über Oxocuprate. XI. Zur Kenntnis von Ba3Cu2O4Cl2

On Osocuprates. XI. Ba₃Cu₂O₄Cl₂ A new oxohalogenocuprat, Ba₃Cu₂O₄Cl₂ mas prepared and investigated by X-ray single crystal methods. The hitherto unknown compound has orthorhombic symmetry (Space group: D_2h⁵—Pmma; a = 6.653, b = 6.000, c = 10.563 Å). It shows angled chains of O^2?-squares around Cu²⁺. One of the Cu²⁺ positions is completed by Cl^minus; to a tetragonal pyramid. The coordination polyhedrals of Ba_I–III and the connection with the Cu/O-chains are described and discussed.     

Fluctuation in occupancy of Cu2+ ions in Zn- and Cd-substituted Cu-ferrites

Mössbauer effect technique has been used for the comparative study of Cu_1?x Zn _x Fe₂O₄ and Cu_1?x Cd _x Fe₂O₄ ( _x = 0.0?1.0) ferrites. Both Zn²⁺ and Cd²⁺ cations are divalent, non-magnetic ions with different ionic radii. With the substitution of these non-magnetic cations the average internal magnetic field decreases and paramagnetic behavior is dominated at x = 0.7 in both series. It is observed that the occupancy of Cu²⁺ ions for tetrahedral site is not constant for all compositions but fluctuate between 8–15%. It is also found that Cu²⁺ ions have more preference for tetrahedral site in Cu-Zn system as compared to the Cu-Cd system. Zn²⁺ and Cd²⁺ both ions occupy tetrahedral site completely and form normal spinels for x = 1.0.     

Zur Kristallchemie der Oxoplatinate

On the Crystal Chemistry of Oxoplatinates Referring to the coordination of Pt²⁺ and Pt⁴⁺ by oxygen the crystal structures of oxoplatinates will be systemized. Pt²⁺ exclusively shows in solids a square and planar coordination well known and typical for Cu²⁺, Pd²⁺ and Ni²⁺ too. Often mixed valences (Pt²⁺/Pt⁴⁺) are observed in square planar oxygen surrounding. Some exceptionally rare coordination is the dumbbell like O—Pt²⁺—O. The crystal chemistry of Pt⁴⁺ resembles the countless metal ions showing octahedral coordination by oxygen. Despite different compositions the compounds BaLn₂PtO₅, Ba₃Cu₂Ln₂PtO₁₀, Ba₅Ln₈Zn₄O₂₁, Ba₁₃Ln₈Zn₄Pt₄O₃₇ and Ba₁₇Ln₁₆Zn₈Pt₄O₅₇ show amazing relationships of polyhedra connections. Additionally will be shown that Ba₄Sm₄Zn₃PtO₁₅ is isotypic to Ba₆Nd₂Al₄O₁₅ and Ba₄NaCu_{0, 5}Pt_{1, 5}O₈ to Ba₁₅Pt₆O₂₇. Oxoplatinates containing lone pair active elements show one side open polyhedra. The positions of the free (s²) electrons are calculated using the Coulomb terms of lattice energy.     

Synthese und Kristallstruktur von Ba6Lu4Zn10O22 mit [OBa6]-Oktaedern

On the Synthesis and Crystal Structure of Ba₆Lu₄Zn₁₀O₂₂ with [OBa₆] Octahedra Single crystals of Ba₆Lu₄Zn₁₀O₂₂ have been prepared by high temperature reactions and investigated by X-ray techniques. This compound is isotypic to Ba₃In₂Zn₅O₁₁ and the first member of the Rare Earth elements. Ba₆Lu₄Zn₁₀O₂₂ crystallizes with cubic symmetry, space group T-F4 3m, a = 13.452(1) Å and Z = 4. Zn²⁺ shows a tetrahedral, Lu³⁺ an octahedral and Ba²⁺ a three-fold capped trigonal prismatic coordination by O^2?. The ZnO₄ tetrahedra and LuO₆ octahedra are forming macro polyhedra of the type Zn₁₀O₂₀ and Lu₄O₁₆. A discussion is given for the Ba₆O₃₃ and Ba₆O₄₂ groups.     

Metal binding and interdomain thermodynamics of mammalian metallothionein-3: enthalpically favoured Cu+ supplants entropically favoured Zn2+ to form Cu4+ clusters under physiological conditions

Metallothioneins (MTs) are a ubiquitous class of small metal-binding proteins involved in metal homeostasis and detoxification. While known for their high affinity for d¹⁰ metal ions, there is a surprising dearth of thermodynamic data on metals binding to MTs. In this study, Zn²⁺ and Cu⁺ binding to mammalian metallothionein-3 (MT-3) were quantified at pH 7.4 by isothermal titration calorimetry (ITC). Zn²⁺ binding was measured by chelation titrations of Zn₇MT-3, while Cu⁺ binding was measured by Zn²⁺ displacement from Zn₇MT-3 with competition from glutathione (GSH). Titrations in multiple buffers enabled a detailed analysis that yielded condition-independent values for the association constant (K) and the change in enthalpy (ΔH) and entropy (ΔS) for these metal ions binding to MT-3. Zn²⁺ was also chelated from the individual α and β domains of MT-3 to quantify the thermodynamics of inter-domain interactions in metal binding. Comparative titrations of Zn₇MT-2 with Cu⁺ revealed that both MT isoforms have similar Cu⁺ affinities and binding thermodynamics, indicating that ΔH and ΔS are determined primarily by the conserved Cys residues. Inductively coupled plasma mass spectrometry (ICP-MS) analysis and low temperature luminescence measurements of Cu-replete samples showed that both proteins form two Cu₄⁺–thiolate clusters when Cu⁺ displaces Zn²⁺ under physiological conditions. Comparison of the Zn²⁺ and Cu⁺ binding thermodynamics reveal that enthalpically-favoured Cu⁺, which forms Cu₄⁺–thiolate clusters, displaces the entropically-favoured Zn²⁺. These results provide a detailed thermodynamic analysis of d¹⁰ metal binding to these thiolate-rich proteins and quantitative support for, as well as molecular insight into, the role that MT-3 plays in the neuronal chemistry of copper.

Metallothioneins (MTs) are a ubiquitous class of small metal-binding proteins involved in metal homeostasis and detoxification.     

Une nouvelle famille structurale: Les oxydes Ln4−2xBa2+2xZn2−xO10−2x (Ln = La,Nd)

Two original compounds, Ln_4?2xBa_2+2xZn_2?xO_10?2x, were isolated for Ln = La, Nd and 0 ≤ x ≤ 0.25. These oxides are tetragonal with a and c parameters close to 6.91 and 11.59 Å, respectively, for lanthanum, and 6.75 and 11.54 Å for neodymium. The structure of these phases was determined from X-ray powder patterns in the most symmetric space group, $\text{I}\text{4}\text{mcm}$, using Patterson and Fourier functions for x = 0. The structure should be compared to that of copper oxides La_4?2xBa_2+2xCu_2?xO_10?2x: it is built up of identical Ln₂O₅ layers formed from face- and edge-sharing LnO₈ polyhedra, between which Ba²⁺ and Zn²⁺ ions are inserted. Contrary to the copper compounds, two successive Ln₂O₅ layers are rotated by 90°, involving a doubling of c. The result for Zn²⁺ is tetrahedral coordination, while the coordination of Ba²⁺ becomes a bicapped antiprism.     

Über ternäre Oxocuprate. X. Zur Kenntnis von Ba2Cu3O4Cl2

About Ternary Oxocuprates. X. On Ba₂Cu₃O₄Cl₂ The preparation of Ba₂Cu₃O₄Cl₂ and results by single crystal X-ray methods are described (a = 5.517, c = 13.808 Å; Space group D–I4/mmm). A so far unknown arrangement of square coordinated Cu²⁺ was detected. The Cu²⁺/O^2?-squares are partly completed to a distorted octahedral coordination by two Cl^?.     

Cu4O12-Baugruppen aus planaren CuO4-Polygonen im Barium-Vanadyl-Oxocuprat(II)-phosphat Ba(VO)Cu4(PO4)4

Cu₄O₁₂ Groups Built of Square Planar CuO₄ Polygones in the Barium Vanadyl Oxocuprate(II) Phosphate Ba(VO)Cu₄(PO₄)₄ Single crystals of Ba(VO)Cu₄(PO₄)₄ have been prepared by solid state reactions just below the melting points of the reaction mixtures of BaP₂O₆, Cu₃(PO₄)₂, CuO, V₂O₅ and V₂O₃ in evacuated closed quartz glas tubes. The compound crystallizes with tetragonal symmetry, Space group D? P42₁2, a = 9.560(2), c = 7.160(2) Å, Z = 2. Special and new features of the crystal structure are to each other isolated Cu₄O₁₂ and (VO)(PO₄)₄ groups. The crystal chemistry of the Cu₄O₁₂ groups is discussed with respect to other compounds containing out of plane connected square planar MO₄ polygones.     

Cd2Cu(PO4)2

During an investigation of the insufficiently known system M1O–M2O–X₂O₅–H₂O (M1 = Cd²⁺, Sr²⁺ and Ba²⁺; M2 = Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺ and Mg²⁺; X = P⁵⁺, As⁵⁺ and V⁵⁺), single crystals of the novel compound dicadmium copper(II) bis[phosphate(V)], Cd₂Cu(PO₄)₂, were obtained. This compound belongs to a small group of compounds adopting a Cu₃(PO₄)₂‐type structure and having the general formula M1₂M2(XO₄)₂ (M1/M2 = Cd²⁺, Cu²⁺, Mg²⁺ and Zn²⁺; X = As⁵⁺, P⁵⁺ and V⁵⁺). The crystal structure is characterized by the interconnection of infinite [Cu(PO₄)₂]_n chains and [Cd₂O₁₀]_n double chains, both extending along the a axis. Exceptional characteristics of this structure are its novel chemical composition and the occurrence of double chains of CdO₆ polyhedra that were not found in related structures. In contrast to the isomorphous compounds, where the M1 cations are coordinated by five O atoms, the Cd atom is coordinated by six. The dissimilarity in the geometry of M1 coordination between Cd₂Cu(PO₄)₂ and the isomorphous compounds is mostly due to the larger ionic radius of the Cd cation in comparison with the Cu, Mg and Zn cations. Sharing a common edge, two CdO₆ polyhedra form Cd₂O₁₀ dimers. Each such dimer is bonded to another dimer sharing common vertices, forming [Cd₂O₁₀]_n double chains in the [100] direction. The Cu atoms, located on an inversion centre (site symmetry ), form isolated CuO₄ squares interconnected by PO₄ tetrahedra, forming [Cu(PO₄)₂]_n chains similar to those found in related structures. Conversely, the [Cd₂O₁₀]_n double chains, which were not found in related structures, are an exclusive feature of this structure.     

Cu2+-complexes of polyamino acids in aqueous solutions catalytic activity (H202-decomposition) and structure

The decomposition of H₂O₂ (8 · 10^?3M ) catalyzed by complexes of Cu²⁺ (4 · 10^?4M ) with various oligomers and polymers of glycine, L-lysine or L-glutamic acid was investigated in aqueous solution in the pH range 5–11, at 24°C and at low ionic strength. Previous investigations have shown that the decomposition of H₂O₂ is catalyzed by Cu²⁺-complexes capable of forming Cu²⁺-peroxocomplexes. With increasing pH the catalytic activity of Cu²⁺-complexes with glycine or glycylglycine (1:1) increases while the activity of Cu²⁺-complexes with tri- or tetraglycine (1:1) is comparatively small at higher pH values apparently because in the latter cases the coordination positions of the copper become progressively occupied by the peptides. This interpretation is in accordance with the pH-dependence of the light-absorption spectra of the latter complexes. Cu²⁺-complexes with poly-α, L -lysines of various molecular weights (molar ratios Cu²⁺: lysine residues = 1:15) have a catalytic activity comparable to or higher than that of the complex Cu²⁺-ethylenediamine (1:1), indicating two available coordination positions for formation of peroxo-complexes. On the other hand, the system Cu²⁺-L -lysine (1:15) showed no significant activity probably because all coordination positions at the Cu²⁺ are occupied by lysine. Despite the excess of ligand groups over Cu²⁺ in the polylysine systems the structure of this polyamino acid apparently does not allow its full coordination with these groups under the conditions investigated. Two adjacent chelating ε-amino groups are considered as the main ligand groups of the polymer to each copper ion. The Cu²⁺-poly-α, L -glutamic acid complex examined (Cu²⁺: glutamic acid residues = 1:5) shows comparatively little activity. In this case, absorption spectra indicate formation of hydroxo-complexes at higher pH. Besides the effects of structure, the electrostatic fields of the charged polyelectrolytes polylysine or polyglutamic acid are also considered to affect the rates of catalysis.     

Zur Kristallchemie eines neuen Barium-Lanthanoid-Oxozinkats: Ba2Er2Zn8O13

On the Crystal Chemistry of a New Barium Rare-Earth Oxozincate: Ba₂Er₂Zn₈O₁₃ High temperature reactions led to single crystals of Ba₂Er₂Zn₈O₁₃. It crystallizes with orthorhombic symmetry, space group C¹²_2v? Cmc2₁, a = 6.276, b = 10.871, c = 10.195 Å, Z = 2. The hitherto unknown crystal structure shows Zn²⁺ with tetrahedral, Er³⁺ octahedral and Ba²⁺ cuboctahedral coordination by O^2?. It will be shown that parts of the [Zn₈O₁₃] network are fragments of the ZnO structure showing O^2? within a tetrahedral zinc coordination. A deficit of two O^2? ions per unit cell is focused on two point positions.     

Ein neues Erdalkalimetall-Oxoplatinat-Cuprat Ca3,5Cu0,5PtO6

A new Alkaline-Earth Platinum Copper Oxide: Ca_3.5Cu_0.5PtO₆ Ca_3.5Cu_0.5PtO₆ was prepared and investigated by single crystal X-ray work. (Space group C? C12/m1; a = 9.0743; b = 9.2527; c = 6.4840 Å; β = 91.448°; Z = 4). The crystal structure of the previously unknown compound is closely related to the structure of Sr₃PtCuO₆ and Sr₃IrCuO₆ as well as the rhombohedral phases M₄PtO₆ (M = Ba, Sr, Ca). Typical features of the crystal chemistry are isolated chains of PtO₆ octahedra, alternately allyed by square CuO₄ polygones and trigonal prisms of O^2? around Ca²⁺.     

Metal Complexes with Macrocyclic Ligands,V. Formation and dissociation kinetics of the pentaco-ordinated Ni2+, Cu2+, Co2+ and Zn2+ complexes with 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane

The formation and dissociation kinetics of the pentaco-ordinated Cu²⁺, Ni²⁺, Co²⁺ and Zn²⁺ complexes with 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (4-MeCyclam-14) was studied by pH-stat techniques and spectrophotometrically. The rates of the reactions between 4-MeCyclam-14 and each of the four metal ions, although slower than normal complexations by a factor of 10³?10⁴, closely follow the order Cu²⁺ > Zn²⁺ > Co²⁺ > Ni²⁺, found for the rate of water exchange. This implies that beside water exchange an other constant factor plays an important role in the rate determing step. The dissociation of the pentaco-ordinated 4-MeCyclam-14 complexes is acid catalyzed. The limiting rate for acid dissociation is not reached even in 2.5M HNO₃ in the case of Ni(4-MeCyclam-14)²⁺. From the formation and dissociation rates stability constants have been calculated, which do not show any macrocyclic effect.     

Ein neues Alkali-Erdalkalimetall-Kupfer-Oxovanadat: Kba3Ca4Cu3V7O28

A new Alkaline-Alkaline-Earth-Copper-Oxovanadate: Kba₃Ca₄Cu₃V₇O₂₈ . Single crystals of Kba₃Ca₄Cu₃V₇O₂₈ were prepared by solid state reactions below the melting point of the reaction mixture. It crystallizes with hexagonal symmetry, space group C?P6₃mc, a=11.160, c=12.428 Å, Z=2. Kba₃Ca₄Cu₃V₇O₂₈ represents a new structure type with special coordination polyhedra around Ba²⁺, trigonal prisms and octahedra around Ca²⁺ and Cu²⁺ inside square pyramids. The crystal structure will be shown and discussed.     

Zur Kenntnis eines Oxoargentato(I)-aurats(III): Ba4AgAuO6

On the Oxoargentato(I)-aurat(III): Ba₄AgAuO₆ The hitherto unknown compound Ba₄AgAuO₆ was prepared by oxidizing Ba/Au/Ag alloy with BaO₂/Ba(OH)₂ mixture in closed Ag tubes. X-ray single crystal investigation led to orthorhombic symmetry space group D-Cmcm; a = 13.275; b = 5.782; c = 11.396 Å; Z = 4. Ba₄AgAuO₆ shows distorted pentagonal bipyramidal polyhedra around Ba²⁺ and square planar AuO₄ polygones. Ag⁺ shows an unusual 2 + 2 coordination by O^2?.     

Zur Kenntnis von Ba10Fe8Pt2Cl2O25

About Ba₁₀Fe₈Pt₂Cl₂O₂₅ The crystal structure of Ba₁₀Fe₈Pt₂Cl₂O₂₅ has been solved by direct methods, using intensity data collected by means of an automatic diffractometer (MoKα). It crystallizes in the hexagonal space group D–P6₃/mmc: a = 5.8034(4) Å, c = 24.997(5) Å, Z = 1. Fe³⁺ ions occur in both octahedral and tetrahedral coordination. Two types of Ba²⁺ ions are formed, with ten and twelve neighbouring atoms. The structure consists of plane connected FeO₆ and PtO₆ octahedra which are connected by corner shared FeO₄ tetrahedra.     

Cu2+ in trigonal-bipyramidaler Koordination: Die Struktur des CuGaInO4

Cu²⁺ in Trigonal-bipyramidal Coordination: Structure of CuGaInO₄ CuGaInO₄ crystallizes in space group R3 m with the hexagonal unit cell parameters a = 335.4(3) and c = 2481(5) pm (Z = 3). The anions form a 12-layer structure with the sequence (31)₃. Indium has a position between cubically packed oxygen layers and possesses a (trigonally-compressed) octahedral coordination. Cu²⁺ and Ga³⁺ – with positions near to the oxygen layers of hexagonal sequence – have a trigonal-bipyramidal coordination (distorted: C_3v). Polyhedra of the same kind form layers by mutual connections via common edges. Polyhedra of different kind are connected with each other along the 3 -axis by common corners.