Reactions of the pentacyanocobaltate(II) ion *1II. Liquid phase hydrogenation and decomposition

Vries, B. De

doi:10.1016/0021-9517(62)90121-5

Cited by 55 publications

References 9 publications

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“…where the designation [FI(Co)t] is used to indicate the sum of the concentrations of two forms of the hydridocobaloxime as shown in the equilibrium HCo(dmgH)2P(n-C4H9)3 ± H+ HCo(dmgH)(dmgH2)P(n-C4H9)3+ (8) Confirmation of eq 7 is found in the plots of log (rate), vs.…”

Section: Resultsmentioning

confidence: 69%

Mechanism of hydrogen evolution from hydridocobaloxime

Chao¹,

Espenson²

1978

J. Am. Chem. Soc.

122

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Section: Resultsmentioning

confidence: 69%

Mechanism of hydrogen evolution from hydridocobaloxime

Chao¹,

Espenson²

1978

J. Am. Chem. Soc.

122

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“…-95 (7) 0 (7) 6 The standard deviations in the last significant figure are given in parentheses in this and succeeding tables. c For the Ba(l) and 0(8) atoms in special positions (4e) on twofold axes, ß« and ß23 are required by symmetry to be zero.…”

Section: Methodsmentioning

confidence: 93%

“…P. Hanson, F. Herman, J. D. Lea, and S. Skillman, Acta Crystallogr., 17, 1040 (1964); those of Ba2+ are from D. T. Cromer and J. T. Waber, Acta Crystallogr., 18, 104 (1965). Real and imaginary corrections for anomalous dispersion for Mo Ka radiation were applied in the final least-squares cycles for the Ba2+ cations and Co atoms (i.e., /' = -0.4 and Af" = 3.0 for barium; /' = 0.4 and /" = 1.1 for cobalt).42 (14) °The superscripts refer to the following symmetry operations: 6 Only ten of the 18 edges of the distorted dodecahedron about Bail)24" are independent due to the C2-2 crystallographicjite symmetry. 'The nomenclature corresponding to the four types of edges (viz., a(2), 6(4), m(4), g( 8)) possessed by a regular DuA2m dodecahedron is given by J. L. Hoard and J. V. Silverton, Inorg.…”

Section: Methodsmentioning

confidence: 99%

Preparation and structure of barium decacyanodicobaltate(II) tridecahydrate, Ba3[CO2(CN)10].13H2O. Stereochemical analysis of the metal-metal bonded [Co2(CN)10]6- dimer

Simon¹,

Adamson²,

Dahl³

1972

J. Am. Chem. Soc.

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The preparation of purple Ba3[Co2(CN)io] • 13H20 (an air-stable salt in striking contrast to the potassium salt) by reaction of an aqueous solution of Co(N03)2• 6H20 with Ba(CN)», and its subsequent characterization by single-crystal X-ray diffraction, not only has resolved all doubt regarding the architecture of the heretofore structurally elusive [Co2(CN)i0]6_ anion but also has furnished detailed structural parameters for comparison with those of related complexes. This binuclear cobalt anion (of crystallographic site symmetry C2 relating the two Co(CN)53halves to each other) was found to conform ideally to the Did-82m Mn2(CO)io-type structure stabilized by a Co(II)-Co(II) bond of length 2.798 (2) Á. An unexpected structural feature (which contrasts that in Mn2(CO)i0) is the Co-CN(ax) bond length of 1.961 (9) A being significantly longer by 0.075 Á than the average value of 1.886 (4) Á for the Co-CN(eq) distances which range from 1.876 (8) to 1.896 (8) A. A comparison of the metal-metal and metal-ligand bond lengths in the [Co2(CN)i0]6-anion with those in the electronically and structurally equivalent Mn2(CO)u> and the [Co2(CNCH3)h>]4+ cation is made, and the differences are rationalized in terms of bonding considerations. The fact that the C-N(ax) bond length of 1.125 (11) Á is 0.04 A shorter (on the borderline of statistical significance) than the average value of 1.165 (5) Á for the C-N(eq) bond lengths of range 1.159 (9)-1.178 (10) Á is utilized along with the intensity variations of the three infrared-allowed cyanide frequencies to provide a tentative vibrational assignment which is different from the known vibrational assignment of the corresponding infrared carbonyl bands in Mn2(CO)10. Ba3[Co2(CN)i0] • 13H20 crystallizes to give a monoclinic unit cell of dimensions a = 9.414 (1) A, b = 20.831 (4) A, c = 15.126 (2) A, ß = 93.457 (4)°, and of symmetry C2/c. The structural determination and least-squares refinement were based on 1761 independent data (/ > 2 (/)) collected by counter methods. Although the initial X-ray results indicated the formula as a dodecahydrate, the presence of the 13th water was shown both from complete elemental analysis and from density measurement (viz., pobsi = 2.305 (5) g cm-3 vs. Pealed = 2.295 g cm-3 for Z = 4) and subsequently substantiated from an anisotropic least-squares model (based on a statistical crystalline disorder of only this crystallographically independent 13th water oxygen atom) which yielded an unweighted Ri of 3.5% and a weighted i?2 of 5.3 %.The cyanocobalt(II) system in solution has generated widespread interest over a long period of time due to its remarkable catalytic properties in various hydrogenation reactions,2•3 to its facility in producing scission of small molecules such as H2,2-4 Br2,5 I2,5 H20,6 H202,7 HONH2,7 ICN,7 and various organic halides,8•9 and to its unusual ability in forming a variety of bridged complexes, [(NC)6Co-L-Co(CN)6]6-, by coordination with various reagents. Examples of the ligand-bridged species include L being peroxo,1011 cya...

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“…Perhaps the addition of acetylenes to cobalt octacarbonyl (29) should be considered an insertion reaction even though the metal-metal bond is not broken since the acetylene finally is bonded to both addition reactions take place with bis-cyclopentadienylnickel carbonyl dimer (93).Changing from carbonyl to cyanide ligands seems to allow the formation of a true vinyl derivative. Thus, potassium pentacyanocobaltate, which may react as a dimer with a cobalt-cobalt bond(20), reacts with acetylene to give the adduct XV (31). The product was thought to be the trans isomer, but the data were not conclusive.Ke[Co(CN)…”

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confidence: 99%

Insertion Reactions of Metal Complexes

Heck¹

1965

Advances in Chemistry

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The insertion reaction is encountered with surprising frequency in organometallic chemistry. Many types of unsaturated molecules undergo the reaction with many different metal compounds. For example, compounds containing metal-hydrogen, metal-carbon, metal-oxygen, metal-nitrogen, metal-halogen, and metal-metal bonds have reacted with one or more of the following unsaturated compounds: carbon monoxide, olefins, dienes, acetylenes, carbonyl compounds, and cyanides. There are still many gaps in our knowledge of the insertion reaction, but already it has been applied in numerous unusual and useful chemical syntheses.Jhe reaction mechanism of the various metal complexes clearly have much in common.The recently recognized insertion reaction appears to be a parti cularly good example of a reaction which is general among the metal compounds.In the following discussion I intend to point out the generality of the insertion reaction with examples from the literature and from our own work. The most complete series of substantiated insertion reactions involves the organocobalt carbonyl complexes, and these reactions will form the nucleus of the discussion. The insertion reaction is the addition of a covalent metal compound, M-X, to a neutral unsaturated molecule, :Y, forming a new complex where the unsaturated molecule has inserted itself between the metal and the atom which was initially bonded to the metal. M-Z + :Y -> M-Y-ZThe unsaturated molecule :Y may be carbon monoxide, an olefin, a conjugated diene, an acetylene, a carbonyl compound, various unsaturated carbon-nitrogen compounds, or probably any of several other unsaturated materials. The reactive part of the covalent metal compound is usually a metal-hydrogen, metal-carbon, metal-oxygen, metal-halogen, metal-nitrogen, or metal-metal group. This reaction

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Reactions of the pentacyanocobaltate(II) ion *1II. Liquid phase hydrogenation and decomposition

Cited by 55 publications

References 9 publications

Mechanism of hydrogen evolution from hydridocobaloxime

Mechanism of hydrogen evolution from hydridocobaloxime

Preparation and structure of barium decacyanodicobaltate(II) tridecahydrate, Ba3[CO2(CN)10].13H2O. Stereochemical analysis of the metal-metal bonded [Co2(CN)10]6- dimer

Insertion Reactions of Metal Complexes

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