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°.     

Über Reaktionen oxygenierter Kobalt(II)-Chelate. VI. Präparative Darstellung von diastereoisomeren Tetrakis(äthylendiamin)-μ-peroxo-μ-hydroxodikobalt(III)-perchloraten

On Reactions of oxygenated Cobalt(II) Chelates. VI. Preparation of diastereoisomeric tetrakis(ethylenediamine)-μ-peroxo-μl-hydroxo-dicobalt(III) Perchlorates Oxygenation of Co(en)₂²⁺ leads to a mixture of two isomeric forms of [(en)₂Co(O₂, OH)-Co(en)₂] (ClO₄)₃ · H₂O from which the less soluble meso form can be readily crystallized. Further crystallization from the mother liquor yields the racemate ΔΔ/ΔΔ. The pure racemate may be obtained by either of the following methods: (a) By ligand exchange starting from mono bridged [(NH₃)₅CoO₂Co(NH₃)₅] (NO₃)₄ or from doubly bridged [(SCN) (NH₃)₃Co(O₂, OH)Co(NH₃)₃(SCN)] SCN · 2H₂O. (b) By reaction of cis-[Co(en)₂(OH₂)₂]³⁺ with H₂O₂. Reaction (b) proceeds via an intermediate cis-[Co(en)₂(OOH) (OH₂)] (ClO₄)₂ · H₂O which at higher pH reacts with [Co(en)₂(OH) (OH₂)]²⁺ to yield the desired doubly bridged ΔΔ/ΔΔ tetrakis(ethylenediamine)-μ-peroxo-μ-hydroxodikobalt(III)-perchlorate.     

Mehrkernige Kobaltkomplexe: Die Struktur von Bis(tri-μ-hydroxo-bis{triamminkobalt(III)}) trisdithionat

Polynuclear Cobalt Complexes: The Structure of Bis(tri-μ-hydroxo-bis{triammine-cobalt(III)})trisdithionate The binuclear complex [(NH₃)₃Co · μ(OH, OH, OH) · Co(NH₃)₃]₂(S₂O₆)₃ crystallizes in the monoclinic space group P2₁/c with lattice constants a = 10.970, b = 9.412, c = 16.069 Å and β = 117.10°. The unit cell contains four cations and six anions. The structure has been determined by an X-ray crystallographic analysis and was refined to R = 0.052.     

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.     

Reaktion oxygenierter Kobalt (II)-Komplexe. XII. Über einen binuclearen μ-Peroxodikobalt (III)-Komplex mit makrocyclischem Brückenring

Reactions of oxygenated cobalt(II) complexes. XII. A binuclear μ-peroxodicobalt(III) complex with a macrocyclic bridging ring

1 XI: siehe [1].

Singly bridged [(tren) (NH₃) CoO₂(NH₃) (tren)]⁴⁺ reacts with excess tren by replacement of NH₃ in cis-position to the peroxo group and formation of a new type of doubly bridged μ-peroxo complex. An X-ray structure determination of [(tren)-Co(O₂, tren)Co(tren)] (ClO₄)₄ · 2 H₂O showed that the additional tren forms a macrocyclic bridging ring. The conformation of the CoOOCo group is transoid with a dihedral angle of 20°. The crystals are monoclinic with space group P2₁/c. The lattice constants are a = 9,798, b = 26,385, c = 16,385 Å, β = 110,2° with four formula units in the cell. The final R value is 0,124. ClO anions are disordered. The reactions of [(tren)Co(O₂, tren)Co(tren)]⁴⁺ in aqueous solution are compared with those of [(tren) (NH₃) CoO₂Co (NH₃tren)]⁴⁺. In acidic solution the new complex mainly decomposes to Co^II and O₂. In alcaline medium the bridging tren is replaced by an OH bridge, forming the well characterized doubly bridged [(tren)-Co(O₂, OH)Co(tren)]³⁺. Differing from the singly bridged bis (ammino) complex, the reactions of which show no pH dependency at all, the decomposition of the tren bridged complex is H⁺-catalyzed. The kinetic data have been interpreted as (i) preceding fast protonation step which is followed by a conformational change of the bridging ring, (ii) acid hydrolysis of a Co-μ-tren bond and (iii) fast cleavage of the Co-OO bond which is labilized by coordinated H₂O.     

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. 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.     

Poly[aqua(μ3‐benzene‐1,2‐dicarboxylato)bis(μ3‐hydroxido)bis(μ2‐isonicotinato)dierbium(III) monohydrate] and the thulium analogue

The two isomorphous lanthanide coordination polymers, {[Ln₂(C₆H₄NO₂)₂(C₈H₄O₄)(OH)₂(H₂O)]·H₂O}_n (Ln = Er and Tm), contain two crystallographically independent Ln ions which are both eight‐coordinated by O atoms, but with quite different coordination environments. In both crystal structures, adjacent Ln atoms are bridged by μ₃‐OH groups and carboxylate groups of isonicotinate and benzene‐1,2‐dicarboxylate ligands, forming infinite chains in which the Er...Er and Tm...Tm distances are in the ranges 3.622 (3)–3.894 (4) and 3.599 (7)–3.873 (1) Å, respectively. Adjacent chains are further connected through hydrogen bonds and π–π interactions into a three‐dimensional supramolecular framework.     

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).     

Diaquatetrakis(tert‐butyl isocyanide)cobalt(II) bis(perchlorate): an example of cobalt(II) coordinated by only four alkyl isocyanide ligands

The title compound, [Co(C₅H₉N)₄(H₂O)₂](ClO₄)₂, crystallizes in the monoclinic space group C2/m. The cation has space‐group‐imposed 2/m symmetry, while the perchlorate ion is disordered about a mirror plane. The two slightly non‐equivalent Co—C bonds [1.900 (3) and 1.911 (3) Å] form a rectangular plane, with a C—Co—C bond angle of 86.83 (11)°, and the linear O—Co—O C₂ axis is perpendicular to this plane. The C[triple‐bond]N bond lengths are 1.141 (4) Å and the Co—C[triple‐bond]N and C[triple‐bond]N—C angles average 175.5 (4)°. The perchlorate counter‐ions are hydrogen bonded to the water molecules. The title compound is the first example of four alkyl isocyanide ligands coordinating Co^II upon initial reaction of Co(ClO₄)₂·6H₂O/EtOH with alkyl isocyanide. In all other known examples, five alkyl isocyanide molecules are coordinated, as in [(RNC)₅Co—Co(CNR)₅](ClO₄)₄ (R = Me, Et, CHMe₂, CH₂Ph, C₄H₉‐n or C₆H₁₁) or [Co(CNC₈H₁₇‐t)₅](ClO₄)₂. This complex, therefore, is unique and somewhat unexpected.     

Komplexchemie des Gallium(III) mit makrozyklischen Liganden Darstellung und Kristallstruktur von Di-μ-hydroxo-μ-acetato-bis[(1,4,7-triazacyclononan)gallium(III)]triiodid · Monohydrat

Coordination Chemistry of Gallium(III) with Macrocyclic Ligands. Synthesis and Crystal Structure of Di-μ-hydroxo-μ-acetato-bis[(1,4,7-triazacyclononane)gallium(III)] Triiodide · Monohydrate The coordination chemistry of 1,4,7-triazacyclononane (L) and N,N′,N″-trimethyl-1,4,7-triazacyclononane (L′) with gallium(III) has been investigated. Monomeric species LGaCl₃ and L′GaCl₃ have been isolated from nonaqueous solutions of GaCl₃ and the respective amine. From alkaline, aqueous solutions of Ga(NO₃)₃, and the respective amine binuclear complexes have been isolated; [L₂Ga₂(OH)₂(μ-OH)₂](ClO₄)₂ · 5 H₂O, [L₂Ga₂(μ-CH₃CO₂)(μ-OH)₂]I₃ · H₂O. [L′₂Ga₂(μ-OH₂CH₃CO₂)₂](ClO₄)₄ · H₂O was obtained from a methanolic solution of Ga(NO₃)₃ and NaCH₃CO₂. [L₂Ga₂(μ-OH)₂(μ-CH₃CO₂)]I₃ · H₂O crystallizes in the monoclinic space group P2₁/a (Z = 4); two Ga^III-centers are connected via two OH- and one acetato-bridge.     

trans‐Cyano(6‐methyl‐1,4,8,11‐tetraazacyclotetradecan‐6‐amine)cobalt(III) bis(perchlorate) hydrate and trans‐hydroxo(6‐methyl‐1,4,8,11‐tetraazacyclotetradecan‐6‐amine)cobalt(III) bis(perchlorate)

The crystal structures of a pair of closely related macrocyclic cyano‐ and hydroxopenta­amine­cobalt(III) complexes, as their perchlorate salts, are reported. Although the two complexes, [Co(CN)(C₁₁H₂₇N₅)](ClO₄)₂·H₂O and [Co(OH)(C₁₁H₂₇N₅)](ClO₄)₂, exhibit similar conformations, significant differences in the Co—N bond lengths arise from the influence of the sixth ligand (cyano as opposed to hydroxo). The ensuing hydrogen‐bonding patterns are also distinctly different. Disorder in the perchlorate anions was clearly resolved and this was rationalized on the basis of distinct hydrogen‐bonding motifs involving the anion O atoms and the N—H and O—H donors.     

μ‐Oxo‐bis{[(6‐hydroxy­methyl‐2‐pyridyl­methyl)­bis(2‐pyridyl­methyl)­amine‐κ5N,N′,N′′,N′′′,O]­iron(III)} tetrakis­(perchlorate)

The novel μ‐oxo‐diiron complex [Fe₂O(BPHPA)₂](ClO₄)₄ [BPHPA is (6‐hydroxy­methyl‐2‐pyridyl­methyl)­bis(2‐pyridyl­methyl)­amine, C₁₉H₂₀N₄O], contains a binuclear centrosymmetric [Fe₂O(BPHPA)₂]⁴⁺ cation (the bridging O atom lies on an inversion centre) and four perchlorate anions. Each iron ion is coordinated by four N atoms [Fe—N = 2.117 (5)–2.196 (5) Å] and one O atom [Fe—O = 2.052 (5) Å] from a BPHPA ligand, and by one bridging oxo atom [Fe—O = 1.7896 (9) Å], forming a distorted octahedron. There are hydrogen bonds between the hydroxy group and perchlorate O atoms [O—H·O = 2.654 (7) Å].     

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).     

Preparation and Structure of Melemium Melem Perchlorate HC6N7(NH2)3ClO4·C6N7(NH2)3

A new perchlorate salt of melem (2,6,10‐triamino‐s‐heptazine, C₆N₇(NH₂)₃) was obtained from an aqueous solution of HClO₄ at lower concentration than the ones reported for the synthesis of melemium perchlorate monohydrate (HC₆N₇(NH₂)₃)ClO₄·H₂O. The new salt was identified as melemium melem perchlorate (HC₆N₇(NH₂)₃)ClO₄·C₆N₇(NH₂)₃ representing a melem adduct of water free melemium perchlorate. The crystal structure was solved by single‐crystal X‐ray methods ( , no. 2, Z = 2, a = 892.1(2), b = 992.7(2), c = 1201.5(2) pm, α = 112.30(3), β = 96.96(3), γ = 95.38(3)°, V = 965.8(4)·10⁶ pm³, 4340 data, 387 parameters, R1 = 0.039). Melemium melem perchlorate crystallizes in a layer‐like structure containing both protonated HC₆N₇(NH₂)₃ and non protonated C₆N₇(NH₂)₃ moieties in the coplanar layers as well as perchlorate ions between them, all of which being interconnected by hydrogen bonds. Vibrational spectroscopic investigations (FTIR and Raman) of the salt were conducted.     

Synthesis and Crystal Structure of meso-Δ,Λ-μ-Peroxo-μ-hydroxobis[bis(ethylenediamine)rhodium(III)]trifluoromethane Sulfonate

The reaction of the meso-diol, Δ,Λ-[(en)₂Rh(OH)₂Rh(en)₂]⁴⁺, with aqueous H₂O₂ and 1 equiv. of NaOH at 90° forms the μ-peroxo-μ-hydroxo-bridged species Δ,Λ-[(en)₂Rh(O₂,OH)Rh(en)₂]³⁺ in a yield of ca. 50%. The compound was crystallized as perchlorate and trifluoromethanesulfonate salts. The structure of the latter salt was determined by single-crystal X-ray diffraction. The crystals are triclinic with space group P1 and lattice constants a = 11.895(5), b = 12.491(4), c = 13.053(5) Å, α = 103.98(3), β = 92.59(3), γ = 119.52(6)°. The distances of the metal centres to the bridging peroxo ligand are 1.999(8) and 1.983(6) Å. The O? O distance in the peroxo group is 1.521(14) Å, and the dihedral angle of the Rh? O? O? Rh unit deviates 65° from planarity. The peroxo complex reacts reversibly with acid, and spectrophotometric studies suggest that the reaction involves protonation of the peroxo bridge, with pK_a = 2.70(2) at 25° in 1M NaClO₄.     

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.     

First Characterization of an Extended Ammonium‐Ammonia Complex [{NH4(NH3)4}+(μ‐NH3)2] in the Crystal Structure of [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3

The compound [NH₄(NH₃)₄][Co(C₂B₉H₁₁)₂] · 2 NH₃ ( 1 ) was prepared by the reaction of Na[Co(C₂B₉H₁₁)₂] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C₂B₉H₁₁)₂]^‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite equation/tex2gif-stack-2.gif[{NH₄(NH₃)₄}⁺(μ‐NH₃)₂] cationic chain, which is formed by [NH₄(NH₃)₄]⁺ ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).     

Di‐μ‐hydroxido‐bis{[bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine‐κ3N′,N′′,N′′′]copper(II)} bis(perchlorate)

The title compund, [Cu₂(OH)₂(C₂₂H₂₅N₃)₂](ClO₄)₂, is a copper(II) dimer, with two [CuL]²⁺ units [L is bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine] bridged by hydroxide groups to define the {[CuL](μ‐OH)₂[CuL]}²⁺ cation. Charge balance is provided by perchlorate counter‐anions. The cation has a crystallographic inversion centre halfway between the Cu^II ions, which are separated by 3.0161 (8) Å. The central core of the cation is an almost regular Cu₂O₂ parallelogram of sides 1.931 (2) and 1.935 (2) Å, with a Cu—O—Cu angle of 102.55 (11)°. The coordination geometry around each Cu^II centre can be best described as a square‐based pyramid, with three N atoms from L ligands and two hydroxide O atoms completing the coordination environment. Each cationic unit is hydrogen bonded to two perchlorate anions by means of hydroxide–perchlorate O—H...O interactions.     

Bond length of perchlorate at different temperatures: X‐ray and neutron comparison

The averages (average deviations from the mean are given in square brackets) of uncorrected Cl—O bond distances in a perchlorate anion from an X‐ray diffraction analysis of (N‐{2‐[bis(pyridin‐2‐ylmethyl)amino]ethyl}pyridine‐2‐carboxamidato)(nitric oxide)manganese perchlorate acetonitrile disolvate, [Mn(C₂₀H₂₀N₅O)(NO)]ClO₄·2CH₃CN or [Mn(PaPy₃)(NO)]ClO₄·2CH₃CN, decrease from 1.447 [4] Å at 10 K to 1.428 [4] Å at 170 K. The 10 K value is close to the neutron value (1.441 [1] Å) at 18 K. Comparisons are made with a second X‐ray study at 30 K [1.444 (8) Å] and to libration‐corrected, density functional theory (DFT), and Cambridge Structural Database (CSD) values.