Di-μ-sulfato-μ-hydroxo-bis[triamminkobalt(III)]- und Di-μ-selenato-μ-hydroxo-bis[triamminkobalt(III)]-Komplexe

Preparation and properties of two new complexes containing the cations [Co₂{(SO₄)₂(OH)}(NH₃)₆]⁺ and [Co₂{(SeO₄)₂(OH)}(NH₃)₆]⁺ are described. The absorption spectra in the infrared. visible and ultraviolet region are reported and discussed.     

Über μ-Carboxylato-μ-hydroxo-bis(triamminkobalt(III))-Komplexe

Report of the preparation, chemical properties, and the infrared-to-ultra-violet spectra of the perchlorates and bromides of the two complex cations [Co₂{ac(OH)₂}(NH₃)₆]³⁺ (where ac = HCO₂, CH₃CO₂; CH₂ClCO₂, CHCl₂CO₂, CCl₃CO₂, CHFCO₂, CHF₂CO₂ und CF₃CO₂) and [Co₂{ac₂(OH)}(NH₃)₆]³⁺ (where ac = CH₂ClCO₂, CHClCO₂ und CCl₃CO₂). The perchlorate, nitrate, bromide and dithionate salts of the tetranuclear complex [Co₄{C₂O₄(OH)₄}(NH₃)₁₂]⁶⁺ are described. The complex reported by WERNER as [Co₂{OH}₂(CH₃CO₂)H₂O(NH₃)₆]Br₃ actually has the formula [Co₂{CH₃CO₂(OH)₂}(NH₃)₆]Br₃ · CH₃COOH.     

Die Kristall- und Molekülstruktur von μ-5-Pyrimidincarboxylato (O,O′)-di-μ-hydroxo-bis[triamminkobalt(III)]perchlorat

Crystal and Molecular Structure of μ-5-Pyrimidinecarboxylato(O,O′)-di-μ-hydroxo-bis-[triamminecobalt(III)]perchlorate μ-5-Pyrimidinecarboxylato(O,O′)-di-[μ-hydroxo-bis(triamminecobalt)(III)]perchlorate, [(NH₃)₃Co-μ(OH, OH, C₅H₄N₂O₂)Co(NH₃)₃](ClO₄)₄, crystallizes in the orthorhombic space group Ibca with a = 12.686, b = 13.079, c = 31.785 Å and Z = 8 formula units. The complex cation adopts C₂ symmetry, but no mirror plane is present. The Co? Co separation in the binuclear complex is 2.794 Å. The four-membered ring defined by the two Co atoms and the bridging oxygens is folded along the O? O axis, the interplanar angle being 154°. One of the ClO₄ tetrahedra is disordered over two sites in the crystal.     

Die Molekül- und Kristallstruktur von Di-μ-sulfato-μ-hydroxo- bis[triamminkobalt(III)]sulfat-8-Hydrat

The crystal structure of Di-μ-sulfato-μ-hydroxo-bis[triamminecobalt(III)] sulfate 8-hydrate has been determined from three-dimensional x-ray data collected by counter techniques. The structure was refined using 2515 independent reflections and the refinement converged to a conventional R factor (on F) of 3.8%. The compound crystallizes in the monoclinic space group C—P2/a, a = 14.122(9), b = 9.858(2), c = 18.81(2) Å, β = 139.3(4), Z = 2, d_obsd = 2.086 g/cm³ and d_calc = 2.14 g/cm³. Within the cation two bidentate SO₄-ligands form bridges between two cobalt atoms. There are two types of S? O bonds (1.50 Å endocyclic, 1.45 Å exocyclic).     

Die Kinetik und der Mechanismus der Reduktion zweier isomerer μ-Cyanobenzoato-di-μ-hydroxo-bis [triamminkobalt(III)] Komplexe mit Chrom(II) und Vanadin(II)

Kinetics and Mechanisms of the Reductions of Two Isomeric μ-Cyanobenzoato-di-μ-hydroxo-bis[triamminecobalt(III)] Complexes by Cr^II and V^II The Cr²⁺ and V²⁺ reductions of the binuclear μ-3-cyanobenzoato-di-μ-hydroxo-bis[triamminecobalt(III)] and its μ-4-cyanobenzoato analog have been studied by conventional spectrophotometric methods at 25°C, I = 1.0 M (LiClO₄). The reactions are first order in oxidant and reductant, and independent of acid ([H⁺] = 0.04–0.97 M). Reduction of the first cobalt is rate determining. Outersphere mechanisms for all reductions are assigned on the basis of k_Cr : k_V ratios (～0.02). The non capacity of cyanobenzoic acids to mediate electrons via an innersphere mechanism (at least for Cr²⁺ reductions) with attack of reductant at the remote nitrogen atom of the organic ligand is interpreted in terms of the non reducibility of the uncomplexed ligands.     

μ-Nitro-μ-hydroxo-bis(tetramminkobalt(III))-Komplexe

The preparation and the properties of 7 salts containing the complex cation [Co₂{NO₂, OH}(NH₃)₈]⁴⁺ are described. Furthermore, a di-μ-hydroxo complex of the composition [Co₂{OH}₂NO₂(NH₃)₇](ClO₄)₃ · H₂O has been prepared.     

μ-Nitro-di-μ-hydroxo-bis[trinitro-kobaltat(III)]-Komplexe

4 complexes containing the anion [Co₂{NO₂(OH)₂}(NO₂)₆]^3? are described. The infrared and Raman spectra are reported and discussed.     

Mehrkernige Kobaltkomplexe. V. Präparative Herstellung von Tetrakis (äthylendiamin)-μ-peroxo-μ-amido- und μ-peroxo-μ-thiocyanatodikobalt (III)-Komplexen ausgehend von Tetrakis (äthylendiamin)bis-(ammin)-μ-peroxo-dikobalt (III)-tetraperchlorat

Polynuclear Cobalt Complexes. V. Preparation of tetrakis (ethylenediamine)-μ-peroxo-μ-amido and μ-peroxo-μ-thiocyanato-dicobalt (III) complexes starting from tetrakis (ethylenediamine)bis-(ammine)-μ-peroxo-dicobalt (III)-tetraperchlorate Racemic tetrakis (ethylenediamine)-μ-peroxo-μ-amido-dicobalt (III) thiocyanate and its corresponding hydroperoxo- and superoxo-complexes have been isolated from [(en)₂(NH₃)Co(O₂)(NH₃)(en)₂](ClO₄)₄. A new binuclear peroxo complex containing thiocyanate as bridging ligand was prepared by the same method. The stretching frequencies of the CN- and CS-group as well as the NCS-bending frequence in the IR. spectrum of [(en)₂Co(O₂, SCN)Co(en)₂](NO₃)₃ suggest that the μ-thiocyanato group is N-bonded (2050, 750, 475 cm^?1). A comparison of IR. spectra of known singly and doubly bridged μ-peroxo complexes is made. Characteristic absorption bands, assignable to ν(O? O) and ν(Co? O) are given.     

Cobalt-Komplexe mit O2-Brücken: Die Struktur von μ-Peroxo-bis[pentaammincobalt(III)]-tetranitrat-dihydrat

Cobalt Complexes with 0₂ Bridges: Structure of μ-Peroxo-bis[pentaamminecobalt(III)] Tetranitrate Dihydrate An X-ray structure determination of the binuclear complex [(NH₃)₅CoO₂Co(NH₃)₅] (NO₃)₄ · 2 H₂O A has been performed; R = 0.051. A crystallizes in the space group P2₁/n with Z = 2 and with lattice constants a = 11.657(5), b = 11.977(6), c = 8.082(4) Å, and β = 91.58(4)°. The complex cation has crystallographic 1 -symmetry. The Co? O? O? Co unit is planar with an O? O distance of 1.472(6) Å. Two of the three crystallographically independent NO₃ groups show disorder.     

Mehrkernige Kobaltkomplexe. I. Darstellung und Struktur von [(tren)Co(O2, OH)Co(tren)](ClO4)3·3H2O

Polynuclear Cobalt Complexes. I. Preparation and Structure of [(tren)Co(O₂, OH) - Co(tren)](ClO₄)₃ · 3H₂O. The title compound is obtained by oxygenation of [Co(tren)(H₂O)₂]²⁺ in alcaline solution. An X-ray structure determination shows that the tertiary nitrogen atoms of both chelate groups are cis to the O₂ bridge.     

Kobalt-Komplexe mit O2-Brücken: Die Struktur der Kationen μ-Hydroxo-μ-peroxo-bis[bis(äthylendiamin) kobalt(III)]3+ und μ-Hydroxo-μ-superoxo-bis[bis (äthylendiamin)kobalt(III)]4+

Cobalt Complexes with O₂ Bridges: The Structure of the Cations μ-Hydroxo-μ-peroxo-bis[bis(ethylenediamine) cobalt (III)]³⁺and μ-Hydroxo-μ-superoxo-bis [bis (ethylenediamine) cobalt (III)]⁴⁺ X-ray structure determinations of one salt of each of the two chemically and structurally closely related dinuclear cobalt cations [(en)₂Co · μ(OH, O₂) · Co(en)₂]³⁺ 1a and [(en)₂Co · μ(OH, O₂) · Co(en)₂]⁴⁺ 1b have been performed. In both cases the cations exist as racemic mixtures of ΔΔ and ΔΔ isomers. The O–O distance in the μ-peroxo cation 1a is 1.465 Å and the Co–O–O–Co torsion angle is 60.7°. The corresponding values for the μ-superoxo cation 1b are 1.339 Å and 22.0°.     

Struktur und magnetische Eigenschaften von Bis{3‐amino‐1,2,4‐triazolium(1+)}pentafluoromanganat(III): (3‐atriazH)2[MnF5]

Structure and Magnetic Properties of Bis{3‐amino‐1,2,4‐triazolium(1+)}pentafluoromanganate(III): (3‐atriazH)₂[MnF₅] The crystal structure of (3‐atriazH)₂[MnF₅], space group P1, Z = 4, a = 8.007(1) Å, b = 11.390(1) Å, c = 12.788(1) Å, α = 85.19(1)°, β = 71.81(1)°, γ = 73.87(1)°, R = 0.034, is built by octahedral trans‐chain anions [MnF₅]^2–_∞ separated by the mono‐protonated organic amine cations. The [MnF₆] octahedra are strongly elongated along the chain axis (<Mn–F_ax> 2.135 Å, <Mn–F_eq> 1.842 Å), mainly due to the Jahn‐Teller effect, the chains are kinked with an average bridge angle Mn–F–Mn = 139.3°. Below 66 K the compound shows 1D‐antiferromagnetism with an exchange energy of J/k = –10.8 K. 3D ordering is observed at T_N = 9.0 K. In spite of the large inter‐chain separation of 8.2 Å a remarkable inter‐chain interaction with |J′/J| = 1.3 · 10^–5 is observed, mediated probably by H‐bonds. That as well as the less favourable D/J ratio of 0.25 excludes the existence of a Haldene phase possible for Mn³⁺ (S = 2).     

Mehrkernige Kobaltkomplexe. II. Herstellung und Struktur von [(tren) (NH3)Co(O2)Co(NH3) (tren)](SCN)4 · 2H2O

Polynuclear Cobalt Complexes. II. Preparation and Structure of [(tren) (NH₃)Co(O₂)Co(NH₃) (tren)](SCN)₄ · 2H₂O The title compound is obtained on oxygenation of [Co(tren)(H₂O)₂]²⁺ in 6M aqueous ammonia or by ligand exchange starting from [(NH₃)₅Co(O₂)Co(NH₃)₅]-(NO₃)₄. An X-ray structure determination was made. The substance forms monoclinic crystals, space group P2₁/c, lattice constants a=10,135, b=8,473, c=19,484 Å, β=108,58°, with two formula units in the cell. The final R is 0,066. The binuclear cation has a center of symmetry, so the Co? O? O? Co unit is planar; the Co? O? O angle is 111,5°. The tertiary nitrogen atoms of both chelate groups are cis to the O₂ bridge, as found in doubly bridged [(tren)Co(O₂,OH)Co(tren)](ClO₄)₃ · 3H₂O. On acidification in solution, the singly bridged cation [(tren) (NH₃)CoO₂Co(NH₃)(tren)]⁴⁺ (a) loses the bound O₂ completely. But unlike the doubly bridged cation b , the rate of dissociation of a is independent of pH (Fig. 5). At higher pH (8–10) bridging a→b (Fig. 2) occurs. Both reactions must have the same rate determining step, the first order rate constants being of the order of 2 · 10^?3 s^?1 (25°, 0,35M KCl).