Preparation and crystal structure of bis(dibenzo-18-crown-6)-(tetrachlorocuprato(II)-Cl,Cl′, Cl″, Cl‴)dipotassium diaqua(dibenzo-18-crown-6)potassium dichlorocuprate(I)-dibenzo-18-crown-6

New mixed complex compound bis(dibenzo-18-crown-6)(tetrachlorocuprato(II)-Cl, Cl′, Cl″, Cl?) dipotassium diaqua(dibenzo-18-crown-6)potassium dichlorocuprate(I)dibenzo-18-crown-6 [(CuCl₄)[K(Db18C6)]₂]·[K(Db18C6)(H₂O)₂]⁺·[CuCl₂]^?·Db18C6 was prepared and its structure was studied by the X-ray structural analysis. The structure was found to be disordered. The asymmetric part of its unit cell contains 1/4 of each of its four components. For a given [CuCl₄]^2? anion its Cu²⁺ cation is disordered over two equally probable positions and its independent Cl atom is disordered over three positions differing by occupancy. In this structure two [K(Db18C6)]⁺ fragment of the complex molecule and the complex cation [K(Db18C6)(H₂O)₂]⁺ are of guest-host type with K⁺ cation as the guest. In this structure the statistically disordered alternating cations and Db18C6 molecules form infinite chains. The statistically disordered [CuCl₂]^? anions also form infinite chains.     

Synthesis and Characterization of New M‐Triazole Complexes (M = Co,Cu, Zn)

Three new complexes with the ligand 3,5‐diamino‐1,2,4‐triazole (Hdatrz), [Co₃(μ₂‐Hdatrz)₆(H₂O)₆]·(NO₃)₈·4H₂O ( 1 ), [Cu₃(μ₂‐Hdatrz)₄(μ₂‐Cl)₂(H₂O)₂Cl₂]·Cl₂·4H₂O·2C₂H₅OH ( 2 ) and {[Zn₂(μ₂‐SO₄) (μ₃‐datrz)₂]·2H₂O}_n ( 3 ) have been synthesized and structurally characterized. Complex 1 has a linear trinuclear mixed‐valence cobalt structure with six neutral triazole ligands in the N(1), N(2)‐bridging mode. The central cobalt atom, Co(1), is coordinated to six nitrogen atoms (octahedral) whereas the terminal cobalt atom, Co(2), is coordinated to an N₃O₃ moiety (octahedral). In complex 1 , the uudd cyclic water clusters, nitrate anions and the trimeric cations are linked to a supramolecular structure. Complex 2 features a linear trinuclear copper(II) core, with four N(1), N(2)‐bridging triazole ligands and two chlorido bridges. The central copper atom is coordinated to an N₄Cl₂ moiety (octahedral) whereas the terminal copper is coordinated to an N₂Cl₂O moiety (square‐pyramidal). In complex 2 , tetrahedral hydrogen bonding interactions play an important role to form a supramolecular network. Complex 3 exhibits a polymeric structure, with N(1), N(2), N(4)‐bridging triazolate ligands and sulfate bridges, in which zinc is coordinated to an N₃O moiety (tetrahedral). In complex 3 , water molecules and sulfate anions construct the sulfate‐water supramolecular chain with hydrogen bonding interactions. In addition, the complexes were investigated by elemental analyses, IR spectroscopic, and thermogravimetric measurements.     

Coordination of metal ions by indolic acids. Complexes of indole-3-carboxylic,indole-3-acetic,indole-3-β-acrylic,indole-N-acetic and indole-N-methyl-2-carboxylic acids with some divalent metal ions

Complexes of formula M(L)₂·nH₂O [M=Co or Ni; L=indole-3-carboxylic (I3CH), indole-3-acetic (I3AH), indole-N-acetic (INAH), indole-N-methyl-2-carboxylic (INMH) and M=Co or Ni and Cu, L=indole-3-β-acrylic acids (I3βH)] were pepared and characaterized by i.r. and electronic spectroscopy and by susceptibility measurements and e.s.r. at room and low temperature. The cobalt and nickel complexes exhibit a distorted octahedral coordination except the Co(I3C)₂ complex for which a tetrahedral coordination was suggested. The Cu(I3β)₂·H₂O shows e.p.r. features that can be interpreted if the triplet state, S=1, depending on the temperature, is able to migrate through the crystal lattice of carboxylate dimers such as the copper(II) acetate monohydrate.     

Synergic extraction of divalent iron,cobalt, copper and zinc with thenoyltrifluoroacetone-dibenzylamine in chloroform

The solvent extraction of divalent iron, cobalt, copper and zinc from perchlorate medium of constant ionic strength (0.1 H⁺, NaClO₄) into a mixture of thenoyltrifluoroacetone (HTTA) and dibenzylamine (DBA) in chloroform has been studied. The extraction of the different cations were found to increase by more than 10³ order of magnitude in presence of DBA. Slope analysis of the extraction results assumed a general formula of M(TTA)₂·DBA for the extractable adduct. A stability order of Fe(TTA)₂·DBA>Co(TTA)₂ ·DBA>Zn(TTA)₂·DBA>Cu(TTA)₂·DBA has been decumented.     

3: 1: 1 Adduct of orthophosphoric acid,dibenzo-18-crown-6, and water: Synthesis and crystal structure

A 3: 1: 1 crystalline adduct of orthophosphoric acid, crown ether dibenzo-18-crown-6, and water, 3H₃PO₄ · Db18C6 · H₂O (I), is synthesized and studied by X-ray diffraction analysis. The orthorhombic structure of compound I (space group Pmn2₁, a = 23.123 Å, b = 12.595 Å, c = 4.922 Å, Z = 2) is solved by a direct method and refined by full-matrix least squares in the anisotropic approximation to R = 0.061 by all 1894 independent reflections. One H₃PO₄ molecule and Db18C6 and H₂O molecules lie on the crystallographic plane m. The H₃PO₄ molecules are randomly disordered. The H atoms of the H₃PO₄ and H₂O molecules are not objectively revealed because of high disordering. The Db18C6 and H₂O molecules form the host-gust molecular complex [Db18C6 · H₂O] through hydrogen bonds. All H₃PO₄ molecules are hydrogenbonded to form infinite layers lying parallel to the xz plane. The [Db18C6 · H₂O] molecular complexes are arranged between the layers.     

Potassium bis­(carbonato‐O,O′)(ethylenedi­amine‐N,N′)­cobaltate(III) monohydrate at 173 K

The title salt, K[Co(C₂H₈N₂)(CO₃)₂]·H₂O, consists of a distorted octahedral cobalt complex anion and a seven‐coordinate potassium cation. Both metal atoms have crystallographic twofold symmetry, one C₂ axis passing through the Co atom and C—C bond, and another along a short K—O (water) bond of 2.600 Å (corrected for libration). The carbonate is bidentate to both cobalt and potassium and the water forms a hydrogen bond to a carbonate O atom.     

Crystal structure of the new compound Co6(TeO3)2(TeO6)Cl2

The new compound Co₆(TeO₃)₂(TeO₆)Cl₂ has been isolated during an investigation of the system CoO:CoCl₂:TeO₂. The new compound is deep purple in color and crystallizes in the tetragonal system, space group P4₂/mbc, a=8.3871(7) Å, c=18.5634(19) Å, Z=4. The Co(II) ions have octahedral [Co1O₆] and tetrahedral [Co2O₃Cl] coordinations. Tellurium is present both as Te(IV) with a tetrahedral [Te1O₃E] coordination, where E is the 5s² lone-pair and as Te(VI) with an octahedral [Te2O₆] coordination. The structure is made up of intersecting layers of tetrahedra forming channels comprising octahedra chains that run along the c-axis. The new compound is the first cobalt tellurium oxochloride described.     

Dibenzo-18-crown-6 diaqua(dibenzo-18-crown-6)potassium triiodide: Synthesis and crystal structure

A new compound, dibenzo-18-crown-6 diaqua(dibenzo-18-crown-6)potassium triiodide [K(Db18C6)(H₂O)₂)⁺ · I₃⁻ · Db18C6 (I), is synthesized and studied by X-ray crystallography. The crystals of compound I are orthorhombic: a = 22.065 ?, b = 22.140 ?, c = 9.433 ?, Z = 4, space group Pccn. Structure I is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.098 for all 5974 unique reflections. Structure I contains the following asymmetric units: a half of the I₃⁻ centrosymmetric anion and two halves of the mixed equally average [K(Db18C6)(H₂O)₂]⁺ host—guest complex cation (a) and a free Db18C6 molecule, each stacked on the axes 2 of the perpendicularly averaged plane of the eighteen-membered macroheterocycle. In complex I, both Db18C6 molecules (a and b) have a “butterfly” conformation with approximate symmetry C _2v . Original Russian Text ? A.N. Chekhlov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 3, pp. 516–520.     

Synergic extraction of trivalent iron and cobalt with thenoyltriflouroacetone and certain benzylamines in chloroform

Synergic extraction of trivalent iron and cobalt with thenoyltriflouroacetone (HTTA) and the synergic bases (B) benzylamine (BA), dibenzylamine (DBA) and tribenzylamine (TBA) was studied. The extracted adducts proved to have the general formula M(TTA)₃·B for all the amines investigated. The formation constants of the mixed-ligand complexes decrease in the order DBA>TBA>BA. While equilibrium constant β_3,1 for the Co(TTA)₃·DBA complex is higher than the corresponding iron adduct, β_3,1 for the iron adducts with BA and TBA are higher than those for cobalt.     

Three-layered close packing in the crystal structure of tris(ethylenediamine)cobalt(III) hexanitrorhodate(III) hydrate, [Co(en)3][Rh(NO2)6]·3H2O,en=C2H8N2

In the structure of cubic tris(ethylenediamine)cobalt(III) hexanitrorhodate(III) hydrate, [Co(en)₃][Rh(NO₂)₆]·3H₂O, en=C₂H₈N₂, with a=16.540(5) Å, space group Pa3 (nonstandard, reduced to orthorhombic Pcab), the complex cations, anions, and water molecules are arranged by the law of three-layered (fcc) close packing of “quasispherical” species according to two structural types, NaCl and CaF₂. The packing is formed of [Rh(NO₂)₆]^3? anions, which also fill the octahedral voids. The tetrahedral voids are occupied by the central atoms of the [Co(en)₃]³⁺ cations, and the H₂O molecules lie between the cations, performing the packing function: the Ow...N_en contacts of 3.04 Å and the Ow..O_{NO 2} contacts of 3.01 Å characterize weak van der Waals interactions. The values of the interatomic distances Co?N, Rh?N, N?O, N?C, and C?C are in good agreement with the known data.     

Synthesis and characterization of cobalt(III) tetraaza macrocyclic complexes containing chloro and azido ligands

The complexes [Co(L)Cl₂]Cl · 4H₂O (1) and [Co(L)(N₃)₂]N₃ · 2H₂O (2) (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo [14,4,0^1.18,0^7.12]docosane) have been synthesized, and structurally characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The crystal structure of (1) is centrosymmetric and the cobalt(III) atom has an axially elongated octahedral geometry with four nitrogen atoms of the macrocycle and two chloride ligands. The cobalt(III) ion in (2) is coordinated to four nitrogen atoms from the macrocycle, and two azide ligands in an octahedral environment, which forms the 1D polymer through hydrogen bonding contacts involving the cation, azide anion and solvent water molecules. Electronic spectra of the complexes also exhibit a low-spin octahedral environment. Cyclic voltammetry of the complexes undergoes a one-electron wave corresponding to Co(III)/Co(II) processes. The electronic spectra and electrochemical behaviors of the complexes are significantly affected by the nature of the axial ligands.     

Self‐assembly of Two Cobalt(II) Coordination Polymers Derived from Tetrabromoterephthalate and Flexible Bis(Benzimidazole) Co‐ligands

Two new cobalt(II) coordination polymers, {[Co(L1)(tbta)] · 0.8H₂O}_n ( 1 ) and {[Co(L2)(tbta)] · H₂O}_n ( 2 ) [L1 = 1,1′‐(1,3‐propanediyl)bis(2‐methylbenzimidazole), L2 = 1,2‐bis(2‐methylbenzimidazole‐1‐ylmethyl)benzene, H₂tbta = tetrabromoterephthalic acid] were obtained under hydrothermal conditions and structurally characterized by single‐crystal X‐ray diffraction methods, IR spectroscopy, TGA, and elemental analysis. The cobalt atoms present similar environments with tetrahedral arrangements in 1 and 2 . The two complexes show a 2D (4,4) coordination network with sql topology. Compound 2 is further extended into a rare 3 , 3 , 4T3 three‐dimensional supramolecular framework by weak C–H ··· O hydrogen bonding interactions. The fluorescence and catalytic properties of the complexes for the degradation of the congo red azo dye in a Fenton‐like process were investigated.     

Synthesis and characterization of tetrahedrally and octahedrally coordinated mixed-valence Co(II)/Co(III) complex with thiosemicarbazone-based ligand

Synthesis, characterization, and X-ray crystal structure for a mixed-valence binuclear Co(II)/Co(III) complex with the dianionic dithiolate form of a pentadentate ligand 2,6-diacetylpyridinebis(thiosemicarbazone) are reported. A new synthetic methodology has been employed replacing usual cobalt(II) salts by [Co(NH₃)₅Cl]Cl₂ as a precursor. The coordination geometry of cobalt(II), CoN₂S₂, was found to be distorted tetrahedral, whereas the cobalt(III) coordination sphere, CoN₄S₂, is slightly distorted octahedral. The magnetic behavior and molar conductivity of the complex are in agreement with the mixed-valence state.     

Chelate complexes of some NNO tridentate Schiff bases with iron(II), cobalt(II), nickel(II) and copper(II)

Summary The Schiff bases a-(C₅H₄N)CMe=NNHCOR (R = Ph, 2-thienyl or Me), prepared by condensation of 2-acetylpyridine with the acylhydrazines RCONHNH₂, coordinate in the deprotonated iminol form to yield the octahedral complexes, M[NNO]₂ M = Co or Ni; [NNOH] = Schiff base and the square-planar complexes, Pd[NNO]Cl. The Schiff bases also coordinate in the neutral keto form yielding the octahedral complexes (M[NNOH]2)Z2 (M = Ni, Co or Fe; Z = C104, BF₄ or N03) and complexes of the type M[NNOH]X2 (M = Ni, Co, Fe or Cu; X = Cl, Br or NCS). Spectral and x-ray diffraction data indicate that the complexes M[NNOH]X2 (M = Ni or Fe) are polymeric octahedral, as are the corresponding cobalt complexes having R = 2-thienyl. However, the cobalt complexes Co[NNOH]X2 (X = CI or Br; R = Ph or Me) and the copper complexes Cu[NNOH]CI₂ (R = Ph, 2-thienyl or Me) are five-coordinate, while the thiocyanato complex Co[NNOH](NCS)₂ (R = 2-thienyl) is tetrahedral.     

[Co7(μ4‐O)2(O2C–CH3)8(NCO)2(HNPEt3)4] · 2 OEt2, ein siebenkerniger Komplex mit vier‐, fünf‐ und sechsfach koordinierten Cobalt‐Atomen

[Co₇(μ₄‐O)₂(O₂C–CH₃)₈(NCO)₂(HNPEt₃)₄] · 2 OEt₂, a Seven Nuclearity Complex with Four, Five, and Sixfold Coordinated Cobalt Atoms The title compound was prepared from cobalt(II) acetate with Me₃SiNPEt₃ at 180 °C and subsequent crystallization from diethylether to give blue, moisture sensitive single crystals, which were characterized by a crystal structure determination. Space group P2₁/n, Z = 2, lattice dimensions at –80 °C: a = 1544.0(1), b = 1522.1(2), c = 1702.0(1) pm, β = 103.911(10)°, R = 0.0490. [Co₇(μ₄‐O)₂(O₂C–CH₃)₈(NCO)₂ · (HNPEt₃)₄] has a centrosymmetric cluster‐like structure in which the octahedrally coordinated central cobalt atom is connected with the remaining six cobalt atoms via two μ₄‐oxygen atoms as well as via four bridging acetato groups to form a Co(Co)₆ octahedral skeleton. Four of the peripheric cobalt atoms have a distorted trigonal‐bipyramidal coordination sphere, the other two cobalt atoms are tetrahedrally coordinated. The latter are connected with the nitrogen atoms of the cyanato groups.     

Synthesis,spectroscopic, thermal,free radical scavenging ability,and antitumor activity studies of cobalt(II) metformin complex

New [Co(Mfn-HCl)₂(NO₃)₂] · 6H₂O complex has been synthesized and characterized using microanalytical, molar conductance, spectroscopic (IR and UV-Vis), effective magnetic moment, and thermal analyses. The infrared spectroscopic results data received from the comparison between free Mfn · HCl ligand and its cobalt(II) complex proved that Metformin forms complex with cobalt(II) ions as a bidentate ligand through its two imino groups. The antioxidant activity of the Mfn · HCl and Co(II)-2Mfn · HCl complex were evaluated by using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging method. Antitumor activity for Mfn · HCl ligand and its cobalt(II) complex was determined using Ehrlich Ascites carcinoma cell (EACC) line. It has been shown that the Co(II)-Mfn · HCl complex is much more effective as free radical scavenger and has higher antitumor activity than the free Mfn · HCl ligand.     

Temperature Influence on the Formation of Selenidoantimonates: Solvothermal Syntheses,Crystal Structures and Thermal Properties of [Ni(dien)2]2Sb2Se6, [Mn(dien)2]2(SbSe4)(Cl), [Co(dien)2]2(SbSe4)(Br), and [Co(dien)2]3(SbSe4)2

New selenidoantimonats [Ni(dien)₂]₂Sb₂Se₆ ( 1 ), [Mn(dien)₂]₂(SbSe₄)(Cl) ( 2 ), [Co(dien)₂]₂(SbSe₄)(Br) ( 3 ), and [Co(dien)₂]₃(SbSe₄)₂ ( 4 ) (dien = diethylenetriamine) were solvothermally synthesized in dien solvent at 180 °C. The crystal structure of 1 consists of two octahedral [Ni(dien)₂]²⁺ cations and a mixed‐valent [Sb₂Se₆]^4? anion. The isolated [Sb₂Se₆]^4? anion is formed by a Sb^IIISe₃ trigonal pyramid and a Sb^VSe₄ tetrahedron sharing a common corner. 2 and 3 are composed of octahedral [M(dien)₂]²⁺ cations, tetrahedral [SbSe₄]^3? anions and halide ions forming an extended network through hydrogen‐bonding interactions. In 4 the [Co(1)(dien)₂]²⁺, [Co(2)(dien)₂]²⁺ and [SbSe₄]^3? ions form layered structures via N–H···Se hydrogen bonds. The [Co(3)(dien)₂]²⁺ ion is located between the layers, and interacts with the layers by N–H···Se bonds. The synthesis and solid state structural studies on the title compounds show that the higher reaction temperature is helpful for the formation of selenidoantimonate(V) compounds in the synthesis of selenidoantimonate from the M²⁺/Sb/Se/dien system. 1 – 4 start to decompose at temperature about 210 °C in N₂ atmosphere. They lose dien ligands at a wide temperature range of 210–450 °C with multisteps for 1 – 3 and a single step for 4 .     

Self‐Assembly and Structure of Cobalt(II) Complexes Using Diaminodiamide Ligands

The self‐assembly of Co(II) with two diaminodiamide ligands, 4,7‐diazadecanediamide and 4,8‐diazaundecanediamide, gave two different crystals, [(C₈H₁₈N₄O₂)Co(OH)₂Co(C₈H₁₈N₄O₂)]Cl₂ ( 1 ) [Co(C₉H₂₀N₄O₂)(Cl)(H₂O)]·Cl·2H₂O ( 2 ). Structures of 1 and 2 were characterized by single‐crystal X‐ray diffraction analysis. Structural data for 1 shows a novel type of binuclear complex with distorted octahederal coordination geometry around the Co atoms through the hydroxo bridges. By using inter‐connector N‐H···N hydrogen bonding interactions as building forces, each cationic moiety [(C₈H₁₈N₄O₂)Co(OH)₂Co(C₈H₁₈N₄O₂)]²⁺ is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chain‐like structure. The chains are further connected into a 2D layer in a (4,4)‐topology via N‐H···Cl_free hydrogen‐bonding interactions. Structural data for 2 indicate that the cobalt atom adopts a six‐coordinated N₂O₄ environment, giving a distorted octahedral geometry, where two N‐ and two O‐donor sets of ligand located at equatorial positions and one water and one chloride occupied at axial positions. Through NH···Cl‐Co and OH···Cl‐Co contacts, each cationic moiety [Co(C₉H₂₀N₄O₂)(Cl)(H₂O)]⁺ in 2 is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chainlike structure. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to steric strain effect of the diaminodiamide ligand.     

Synthesis and crystal structure of aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)-(tetrachlorocuprato(II)-Cl)potassium

New mixed complex compound aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(tetrachlorocuprato(II)-Cl)potassium, [K(CuCl₄)(Db18C6)]^? · [K(Db18C6)(H₂O)]⁺, is synthesized and its crystal structure is studied by the method of x-ray structural analysis. The structure includes two independent complex ions, both of guest-host type: two cations K⁺ are located in the respective cavities of the Db18C6 crown-ligand (one in each) and each is coordinated by all its six O atoms and one Cl atom of the anion-ligand [CuCl₄]^2? or O atom of the ligand water molecule. Coordination of these two K⁺ cations is completed to hexagonal pyramidal one by formation by each of unusually weak coordination bond K⁺ → π(\(C\dddot - C\)) with two C atoms of respective benzene ring in the neighboring Db18C6 ligand. In this crystal structure the complex anions and cations form dual infinite chains via these coordination bonds and interionic O-H?Cl hydrogen bonds.     

Das Gleichgewicht zwischen oktaedrisch und tetraedrisch koordiniertem Kobalt(II) in N,N-Dimethylacetamid

Zusammenfassung In Lösung von [Co(DMA)₆](ClO₄)₂ in wasserfr. N,N-Dimethylacetamid (DMA) wird spektrophotometrisch ein Gleichgewicht zwischen tetraedrisch und oktaedrisch koordiniertem Co²⁺ festgestellt. Die GleichgewichtskonstanteK=[Co _tetr ²⁺ ]/[Co _oct ²⁺ ] wurde bei 25°C zu 0,028 und bei 70°C zu 0,19 bestimmt. Bei –8°C zeigen die Elektronenspektren keinen meßbaren Anteil der tetraedrischen Species. Für den oktaedrischen Komplex ergibt sichD _q =805 cm^–1,B=834 cm^–1.

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The equilibrium between octahedral and tetrahedral coordinated cobalt(II) in N,N-dimethylacetamide

Spectrophotometric results establish an equilibrium between tetrahedral and octahedral coordinated cobalt(II) in anhydrous N,N-dimethylacetamide (DMA). The equilibrium constantK=[Co _tetr ²⁺ ]/[Co _okt ²⁺ ] has been found to be 0,028 at 25°C and 0,19 at 70°C. Electronic spectra indicate no measurable amount of the tetrahedral species at –8°C. For the octahedral complexD _q =805 cm^–1 andB=834 cm^–1.

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