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  • Inorganic Chemistry  (5)
  • Cobalt complexes  (1)
  • X-ray crystallography  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Ligand displacement reactions from the coordination sphere of cobalt complexes. Part II: The displacement of ligands of [cis-Co(en)2Cl2]Cl by potassium squarate. The crystal and molecular structure of a compound with idealized formula of [cis-Co(en)2(H2O)Br]2[trans-(C2O4 2−(C2O4H−)Co-trans-(H2O)2(OH)2]Br2 (I) (1996)
    Springer
    Structural chemistry 7 (1996), S. 233-240 
    Details
    ISSN: 1572-9001
    Keywords: Cobalt complexes ; potassium squarate ; crystal structure ; molecular structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Compound (I), idealized as Br4Co3O14N8C16H41 (see text), crystallizes in the triclinic space groupP¯ 1 (No. 2) with cell constants ofa=7.4470(7),b=7.9648(4),c=15.2223(8),α=96.338(4)ℴΒ=93.504(6)ℴ,γ=112.894(6)ℴ,V=821.328 å3, and d(calc; MW=1065.97,z=1)=2.155 gm-cm−3. Data (3880 total reflections) were collected over the range 2ℴ ≤ 2θ ≤ 55ℴ and corrected for absorption (Μ=63.69 cm−1) using data from Psi scans. The unexpectedly isolated compound contains a [cis-Co(en)2Br(OH)]+ cation, while the anion contains a central Co(III) surrounded by two mondentate,trans-squarato ligands, twotrans-hydroxo, and two waters. The waters and hydroxy ligands were identified by determining, experimentally, the presence and positions of their respective hydrogens. Given the need for overall electroneutrality, one squarato ligand must be a dianion (Sq2−) and the other a monoanion (SqH−); however, since the ion bearing the squarato ligands sits at an inversion center, the hydrogen of the latter must be disordered. Refinement of the heavy atoms with anisotropic thermal parameters and fixed hydrogen positions (B's fixed at) led to the finalR(F) andR W(F) factors of 0.036 and 0.042, respectively. (I) was obtained during efforts to prepare [Co(en)2(squarate)]Br by the displacement of two chloro ligands from the coordination sphere of [cis-Co(en)2Cl2]Cl by K2 (squarate) followed by addition of NaBr. Compound (I) appears to be the first example of a coordination compound in which squarate2− and squarate H− anions are present as ligands to a transition metal ion. A search of the Cambridge file (to 1992) produced no known examples of Co(III) squarates. Thus, (I) appears to also be the first example of its kind.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02281234
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  • 2
    Electronic Resource
    Electronic Resource
    The phenomenon of conglomerate crystallization in coordination compounds. XXIII: The crystallization behavior of [cis-Co(en)2(N3)(SO3)] · 2H2O (I) and of [cis-Co(en)2(NO2)(SO3)] · H2O (II) (1993)
    Springer
    Structural chemistry 4 (1993), S. 235-245 
    Details
    ISSN: 1572-9001
    Keywords: Conglomerate crystallization ; cobalt complexes ; X-ray crystallography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A room temperature water solution of (I) crystallizes as a racemate, space groupP2 1/n with lattice constantsa=7.737(6),b=10.694(5),c=15.097(6) Å, andβ=102.83(5)°;V=1218.05 Å3 andd (calc; M.W.=337.24, Z=4) = 1.642 g cm−3. A total of 2381 data were collected over the range 4° ≤ 2θ 〈 50°; of these, 1452 (independent and withI ≥ 3σ(I)) were used in the structural analysis. Data were corrected for absorption (μ = 15.76 cm−1), and the relative transmission coefficients ranged from 0.8976 to 0.9984. Refinement led to the finalR(F) andR w(F) residuals of 0.0858 and 0.1116. A room temperature water solution of (II) crystallizes as a racemate in space group P21/c with lattice constantsa=6.638(3),b=11.425(8),c=15.147(16) Å, andβ=93.27(6)°; F=1146.8 Å andd (calc; M.W.=323.2,Z=4) = 1.872 g cm−3. A total of 2200 data were collected over the range 4° ≤ 2θ 〈 50°; of these, 1918 (independent and withI ≥ 3σ(I)) were used in the structural analysis. Data were corrected for absorption (μ=16.94 cm−1), and the relative transmission coefficients ranged from 0.9049 to 0.9967. Refinement led to the finalR(F) andR w(F) residuals of 0.0231 and 0.0279. The chirality symbol for the particular enantiomer of (I) refined here is ∧ (δδ), while for (II) the chirality symbol is ∧(δλ), which means that in the latter compound one of the en rings is in a higher energy conformation. We attribute this result to competitive intramolecular hydrogen-bonded interactions between the — NH2 hydrogens of the en ligands and the oxygens of the -NO2 and -SO3 ligands, strengths which are enhanced by coercing a change in sign of the torsional angle of one en ringa motion which permits both oxo ligands to form stronger hydrogen bonds while retaining proper O ⋯ O contacts. This phenomenon is not observed in (I) since the azide ligand does not compete with -SO3 for such hydrogen-bonded interactions, and nonbonded pair repulsions can be minimized without affecting the ability of — SO3 oxygens to form strong intramolecular hydrogen bonds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00673698
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  • 3
    Electronic Resource
    Electronic Resource
    Metallcarbonyl-Synthesen, X: Synthese neuer Niob- und Tantal-Halbsandwichkomplexe. Molekülstruktur der Stammverbindung (η5-C5H5)Nb(CO)4 (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3558-3571 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalcarbonyl Syntheses, X: Synthesis of New Niobium and Tantalum Halfsandwich Complexes. Molecular Structure of the Parent Compound (η5-C5H5)Nb(CO)4The halfsandwich complexes (η5-C5H4CH3)Nb(CO)4 (3a), [η5-C5(CH3)5]Nb(CO)4 (3b), (η5-C5H4CH3)Ta(CO)4 (3c), and [η5-C5(CH3)5]Ta(CO)4 (3d) are accessible by reductive high-pressure carbonylation of the corresponding NbV- and TaV precursors (η5-C5R4R′)MCl4 (2a-d). Successive introduction of methyl groups in the cyclopentadienyl ring facilitates the reduction of the halogeno complexes 2a-d; moreover, the niobium complexes are more susceptible to reduction than their tantalum counterparts. Upon photolysis of the carbonyl complexes 3a-d in tetrahydrofuran, the solvens complexes of type (η5-C5R4R′)M(CO)3(THF) (4a-d) are generated. The parent compound (η5-C5H5)Nb(CO)4 (1) has a regular square-pyramidal structure as shown by X-ray analysis.
    Notes: Die Halbsandwich-Komplexe (η-5C5H4CH3)Nb(CO)4 (3a), [η5-C5(CH3)5]Nb(CO)4 (3b), (η5-C5H4CH3)Ta(CO)4 (3c) und [η5-C5(CH3)5]Ta(CO)4 (3d) sind durch reduzierende Hochdruckcarbonylierung der entsprechenden NbV-bzw. TaV-vorstufen (η5-C5R4R′)MCl4 (2a-d) synthetisierbar. Die Reduzierbarkeit der Halogeno-Komplexe, 2a-d, wird durch sukzessive Einführung von Methyl-Substituenten in den Cyclopentadienyl-Ring erleichtert und ist bei den Niob-Verbindungen mit milderen Reduktionsmitteln als bei den analogen Tantal-Komplexen möglich. Bei der Photolyse von 3a-d in Tetrahydrofuran entstehen die Solvens-Komplexe (η5-C5R4R′)M(CO)3(THF) (4a-d). Die Stammsubstanz (η5-C5H5)Nb(CO)4 (1) wurde röntgenstrukturanalytisch untersucht und besitzt eine unverzerrt tetragonal-pyramidale Molekülstruktur.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811141109
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  • 4
    Electronic Resource
    Electronic Resource
    Multiple bonds between main group elements and transition metals, III. Synthesis, X-ray crystal and molecular structure of μ-germanium-bis[dicarbonyl(η5-pentamethylcyclopentadienyl)-manganese], μ-Ge-[(η5-C5Me5)Mn(CO)2]2 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 340-347 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen, III Synthese, Einkristall- und Molekülstruktur von μ-Germanium-bis[dicarbonyl(η5-pentamethylcyclopentadienyl)manganl], μ-Ge-[(η5-C5Me5)Mn(CO)2]2Die Titelverbindung 3 wurde nach der Hydrid-Methode durch Behandlung des Solvens-Komplexes (η5-C5Me5)Mn(CO)2(THF) (THF = Tetrahydrofuran) mit Monogerman, GeH4, in Gegenwart von Schwefelsäure synthetisiert. Eine Röntgenstrukturanalysse weist das Vorliegen zweier konformationsisomerer Moleküle im Kristall nach (C/c, monoklin). Bezüglich des streng linearen Mn—Ge—Mn-Gerüsts stehen zwei Carbonyl-Gruppen annähernd auf Deckung, während die anderen beiden anti-Konformation besitzen. Die äquimolar in der Elementarzelle vorlienanden enantiomeren Konformeren leiten sich geometrisch voneinander durch 180°-Drehung einer (η5-C5Me5)Mn(CO)2-Baugruppe um den Mn, Ge, Mn-Vektor ab. Die Mangan  -  Germanium-Bindungslängen betragen 2.18(2) Å (Mittelwert) und weisen damit erheblichen Mehrfachbindungscharakter auf.
    Notes: The title compound 3 has been synthesized along the hydride route by treatment of the solvent complex (η5-C5Me5)Mn(CO)2(THF) (THF = tetrahydrofuran) with monogermane, GeH4, in the presence of sulfuric acid. A single-crystal X-Ray structural analysis revealed two conformers of 3 being present in the solid state in a 1:1 ratio (C2/c, monoclinic). Pairs of carbonyl groups almost eclipse each other, while the remaining two CO ligands an exhibit an anti-conformation relative to the strictly linear Mn—Ge—Mn framework. Both enantiomeric conformers are geometrically related by a 180°-rotation of a (C5Me5)Mn(CO)2 fragment around the Mn, Ge, Mn vector. The manganese  -  germanium bond lenghts average 2.18(2) Å and thus correspond to considerable multiple bonding between these atoms.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180131
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  • 5
    Electronic Resource
    Electronic Resource
    Syntheses of Metal Carbonyls, XVI1). Metal-Metal Multiple Bonds: Synthesis, Crystal and Molecular Structure of Tri-μ-carbonyl-bis[(η5-pentamethylcyclopentadienyl)manganese](Mn ≡ Mn) - The First Manganese-Manganese Triple Bond (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 434-444 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metallcarbonyl-Synthesen, XVI1). Metall-Metall-Mehrfachbindungen: Synthese, Molekül- und Kristallstruktur von Tri-μ-carbonylbis([η5-pentamethylcyclopentadienyl)mangan](Mn ≡ Mn) - die erste Mangan-Mangan-DreifachbindungPhotolyse des Halbsandwich-Mangan-Komplexes (η5-C5Me5)Mn(CO)3 (1) in Tetrahydrofuran (THF) führt ohne Nebenreaktionen zum Solvenskomplex (η5-C5Me5)Mn(CO)2(THF) (2). Dieser ist im festen Zustand im deutlich unter 0°C liegenden Temperaturbereich haltbar, erleidet aber spontane CO-Eliminierung bei Raumtemperatur; dabei bildet sich der neue Zweikernkomplex (η5-C5Me5)2Mn2(μ-CO)3 (3). Während Elementaranalyse, Infrarot- und Massenspektren sowie die 1H- und 13C-NMR-Spektren dieser Verbindung eine hochsymmetrische dreifach Carbonylverbrückte Struktur zuweisen, stützt eine Einkristall-Röntgenstrukturanalyse das Vorliegen der ersten bisher bekannten Mangan-Mangan-Dreifachbindung (dMn - Mn 217.0(1) pm). Eine verbesserte Darstellung von Tricarbonyl(η5-pentamethylcyclopentadienyl)mangan (1) wird beschrieben.
    Notes: Photolysis of the manganese half-sandwich complex (η5-C5Me5)Mn(CO)3 (1) in tetrahydrofuran (thf) cleanly yields the solvent complex (η5-C5Me5)Mn(CO)2(thf) (2). Compound 2 is stable as solid at temperatures well below 0°C but undergoes spontaneous elimination of carbon monoxide at ambient temperature with concomitant formation of the novel dinuclear complex (η5-C5Me5)2-Mn2(μ-CO)3 (3). While elemental analysis, infrared and mass spectroscopy as well as the 1H NMR and 13C NMR spectra unequivocally demonstrate this compound to adopt a highly symmetrical triply carbonyl-bridged structure, a single-crystal X-ray diffraction study supports the presence of the first triple bond between manganese atoms (dMn - Mn 217.0(1) pm). An improved synthesis of tricarbonyl(η5-pentamethylclopentadienyl)manganese (1) is also described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170203
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  • 6
    Electronic Resource
    Electronic Resource
    Transition metal methylene complexes, VII. Studies on metal-metal bonds, V. Preparation and molecular structure of a carbonylcobalt complex containing a novel carbocyclic μ-methylene ligand (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1377-1384 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Übergangsmetall-Methylen-Komplexe, VII Studien über Metall-Metall-Bindungen, V. Darstellung und Molekülstruktur eines Carbonylcobalt-Komplexes mit einem neuartigen carbocyclischen μ-Methylen-LigandenDicarbonyl(η5-cyclopentadienyl)cobalt (1) reagiert mit 2-Diazo-1,3-dioxoindan (2) unter thermischen Bedingungen (siedendes Benzol) unter Bildung des zweikernigen Cobalt-Komplexes 3, der das von 2 abgeleitete Carben als Brückenliganden enthält. Eine Röntgenstrukturanalyse wies nach, daß die beiden Cyclopentadienyl-Ringe ebenso wie die beiden Carbonyl-Gruppen trans-Positionen zueinander einnehmen. Trotz seiner vier Bindungspartner weist das Methylen-Kohlenstoffatom eine sehr stark verzerrte tetraedrische Konfiguration auf [∢Co(1)—C(3)—Co(2): 79.0(1)°, ∢C(4)—C(3)—C(11): 104.3(3)°]. Der Cobalt-Cobalt-Abstand beträgt 247.5(1) pm; die Abstände und Winkel der Co—C(C5H5)- sowie Co—C(CO)-Bausteine sind normal. Das μ-1,3-Dioxoindan-2-yliden-Gerüst ist entlang der Verbindungslinie zwischen den beiden Carbonyl-Kohlenstoffatomen des Dion-Systems um 2° abgewinkelt.
    Notes: Dicarbonyl(η5-cyclopentadienyl)cobalt (1) reacts with 2-diazo-1,3-dioxoindane (2) under thermal conditions (boiling benzene) to yield the dinuclear cobalt complex 3 which contains the carbene derived from 2 as a bridging ligand. An x-ray diffraction study proved that both the cyclopenta-dienyl rings are oriented trans to each other, which is also true for the two metal-carbonyl groups. While four-bonded, the methylene carbon is highly distorted from tetrahedral geometry [∢Co(1)—C(3)—Co(2): 79.0(1)°, ∢C(4)—C(3)—C(11): 104.3(3)°]. The cobalt  -  cobalt distance is 247.5(1) pm and the Co—C(C5H5) and Co—C(CO) distances and angles are normal. The μ-1,3-dioxoindane-2-ylidene backbone is bent by 2° along the vector joining the two carbonyl carbon atoms of the dione system.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130416
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  • 7
    Electronic Resource
    Electronic Resource
    Asymmetrische Katalysen, V. Enantioselektive Aminosäuresynthese durch Hydrierung prochiraler Olefine mit Rh-Komplexen des neuen optisch aktiven chelatbildenden Phosphans Norphos (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1137-1149 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Catalyses, V. Enantioselective Amino Acid Synthesis by Hydrogenation of Prochiral Olefins with Rh-Complexes of the New Optically Active Chelating Phosphane NorphosRacemic bicyclo[2.2.1]hept-5-en-2,3-diylbis(diphenylphosphane oxide), Norphos, can be resolved with (-)-di-O0-benzoyltartaric acid, (-)-DBW. The X-ray structure analysis of the diastereomer (-)-Norphos/(-)-DBW, which is less soluble in ethanol, exhibits strong hydrogen bonds between the carboxylic groups of DBW and the PO groups. The bonding of the DBW-carboxylic groups to different Norphos units leads to the formation of infinite close-packed chains. From the internal comparison with (-)-DBW the absolute configuration follows as (2R, 3R) for (-)-Norphos. The chelating phosphanes (+)-and (-)-Norphos, obtained by SiHCl3-reduction of (+)-and (-)-Norphos, respectively, afford neutral and cationic Rh-complexes which, with H2 at room temperature and atmospheric pressure within a few hours, give quantitative hydrogenation of α-(acetylamino)cinnamic acid, α-(acetylamino)acrylic acid and Dopa precursors. The optical yields very between 79 and 97%.
    Notes: Racemisches Bicyclo[2.2.1]hept-5-en-2,3-diylbis(diphenylphosphan-oxid), Norphos, kann mit Hilfe von (-)-Di-O-benzoylweinsäure, (-)-DBW, optisch gespalten werden. Die Röntgenstrukturanalyse des in Ethanol schwerlöslichen Diastereomeren (-)-Norphos/(-)-DBW zeigt starke Wasserstoffbrücken zwischen den Carboxylgruppen der DBW und den PO-Gruppierungen. Die Bindung der DBW-Carboxylgruppen an verschiedene Norphos-Einheiten führt zur Ausbildung unendlicher dicht gepackter Ketten. Aus dem internen Vergleich mit (-)-DBW folgt für (-)-Norphos die absolute Konfiguration (2R, 3R). Die durch SiHCl3-Reduktion von (+)-bzw. (-)- Norphos erhaltenen chelatbildenden Phosphane (+)-bzw. (-)-Norphos ergeben in neutralen und kationischen Rh-Komplexen bei der Hydrierung von α-(Acetylamino)zimtsäure, α-(Acetylamino)acrylsäure und Dopa-Vorstufen unter Normalbedingungen in wenigen Stunden quantitativ Aminosäurederivate mit optischen Ausbeuten zwischen 79 und 97%.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140331
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