Advertisement

Energetics of Transition Metal-X Bonding Probed by Electrochemical Techniques

  • Mats Tilset
Part of the NATO Science Series book series (ASIC, volume 535)

Abstract

Detailed, quantitative knowledge about the energetics of metal-ligand bonding in organotransition-metal complexes is crucial to the understanding of stoichiometric and catalytic reactions and may eventually help in the design of new and improved processes [1]. While numerous methods are available to estimate the energetics of homolytic as well as heterolytic metal-ligand cleavage reactions, many of these can only be applied under equilibrium conditions. Thus, if the reactions involve transient species, the techniques may not be applicable.

Keywords

Bond Weaken Metal Hydride Bond Dissociation Energy Bond Dissociation Energy Bond Dissociation Enthalpy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    (a) Simões, J. A. M. and Beauchamp, J. L. (1990) Transition Metal-Hydrogen and Metal-Carbon Bond Strengths: The Keys to Catalysis, Chem. Rev. 90, 629–688.CrossRefGoogle Scholar
  2. (b) Simões, J. A. M., Ed. (1992) Energetics of Organometallic Species, Kluwer Academic Publishers, Dordrecht.Google Scholar
  3. (c) Marks, T. J., Ed. (1990) Bonding Energetics in Organometallic Compounds, ACS Symposium Series No. 428; American Chemical Society, Washington, DC.Google Scholar
  4. (d) Halpern, J. (1985) Activation of Carbon-Hydrogen Bonds by Metal Complexes: Mechanistic, Kinetic and Thermodynamic Considerations, Inorg. Chim. Acta 100, 41–48.CrossRefGoogle Scholar
  5. [2]
    Breslow, R. and Chu, W. (1973) Thermodynamic Determination of pK a’s of Weak Hydrocarbon Acids Using Electrochemical Reduction Data. Triarylmethyl Anions, Cycloheptatrienyl Anion, and Triphenyl-and Trialkylcyclopropenyl Anions, J. Am. Chem. Soc. 95, 411–418.CrossRefGoogle Scholar
  6. [3]
    For recent reviews, see: (a) Arnett, E. M., Flowers, R. A. II, Ludwig, R. T., Meckhof, A., and Walek, S. (1995) Thermodynamics for C-H Bond-Breaking of Some Amphihydric Compounds by Transfer of Protons, Hydride Ions, H-Atoms and Electrons, Pure Appl. Chem. 67, 729–734.CrossRefGoogle Scholar
  7. (b) Bordwell, F. G., Satish, A. V., Zhang, S., and Zhang, X.-M. (1995) Using Thermochemical Cycles to Study Reactive Intermediates, Pure Appl. Chem. 67, 735–740.CrossRefGoogle Scholar
  8. (c) Arnett, E. M. and Flowers, R. A. (1993) Bond Cleavage Energies for Molecules and their Associated Radical Ions, Chem. Soc. Rev. 9–15.Google Scholar
  9. (d) Bordwell, F. G. and Zhang, X.-M. (1993) From Equilibrium Acidities to Radical Stabilization Energies, Acc. Chem. Res. 26, 510–517.CrossRefGoogle Scholar
  10. (e) Wayner, D. D. M. and Parker, V. D. (1993) Bond Energies in Solution from Electrode Potentials and Thermochemical Cycles. A Simplified and General Approach, Acc. Chem. Res. 26, 287–294.CrossRefGoogle Scholar
  11. [4]
    For some recommended textbooks that cover fundamental aspects of cyclic voltammetry and other electrochemical techniques, see: (a) Bard, A. J. and Faulkner, L. R. (1980) Electrochemical Methods. Fundamentals and Applications, Wiley, New York.Google Scholar
  12. (b) Sawyer, D. T., Sobkowiak, A., and Roberts, J. L. Jr. (1995) Electrochemistry for Chemists, 2nd ed., Wiley, New York.Google Scholar
  13. (c) Pletcher, D. (1991) A First Course in Electrode Processes, The Electrochemical Consultancy, Ramsey.Google Scholar
  14. (d) Gosser, D. K. Jr. (1993) Cyclic Voltammetry — Simulation and Analysis of Reaction Mechanisms, VCH, Weinheim.Google Scholar
  15. [5]
    (a) Rudolph, M., D., Reddy, D. P., and Feldberg, S. W. (1994) A Simulator for Cyclic Voltammetric Responses, Anal Chem. 66, 589A–600A. (b) DIGISIM simulation software. Trademark of Bio-analytical Systems Inc., W. Lafayette, IN. (c) CVSIM simulation software included with ref [4d].Google Scholar
  16. [6]
    Heinze, J. (1993) Ultramicroelectrodes in Electrochemistry, Angew. Chem., Int. Ed. Engl. 32, 1268–1288.CrossRefGoogle Scholar
  17. [7]
    Connelly, N. G. and Geiger, W. E. (1996) Chemical Redox Agents for Organometallic Chemistry, Chem. Rev. 96, 877–919.Google Scholar
  18. [8]
    Parker, V. D., Handoo, K. L., Roness, F., and Tilset, M. (1991) Electrode Potentials and the Thermodynamics of Isodesmic Reactions, J. Am. Chem. Soc. 113, 7493–7498.CrossRefGoogle Scholar
  19. [9]
    Kiss, G., Zhang, K., Mukerjee, S. L., and Hoff, C. D. (1990) Heat of Reaction of the Cr(CO)3(C5Me5) Radical with H2 and Related Reactions. Relative and Absolute Bond Strengths in the Complexes H-Cr(CO)2(L)(C5R5), J. Am. Chem. Soc. 112, 5657–5658.CrossRefGoogle Scholar
  20. [10]
    (a) Jordan, R. F. and Norton, J. R. (1982) Kinetic and Thermodynamic Acidity of Hydrido Transition-Metal Complexes. 1. Periodic Trends in Group 6 Complexes and Substituent Effects in Osmium Complexes, J. Am. Chem. Soc. 104, 1255–1263.CrossRefGoogle Scholar
  21. (b) Moore, E. J., Sullivan, J. M., and Norton, J. R. (1986) Kinetic and Thermodynamic Acidity of Hydrido Transition-Metal Complexes. 3. Thermodynamic Acidity of Common Mononuclear Carbonyl Hydrides, J. Am. Chem. Soc. 108, 2257–2263.CrossRefGoogle Scholar
  22. (c) Kristjánsdóttir, S. S., Moody, A. E., Weberg, R. T., and Norton, J. R. (1988) Kinetic and Thermodynamic Acidity of Hydrido Transition-Metal Complexes. 5. Sensitivity of Thermodynamic Acidity to Ligand Variation and Hydride Bonding Mode, Organometallics 7, 1983–1987.CrossRefGoogle Scholar
  23. [11]
    (a) Tilset, M. and Parker, V. D. (1989) Solution Homolytic Bond Dissociation Energies of Organotransition Metal Hydrides, J. Am. Chem. Soc. 111, 6711–6717, and corrigendum (1990) ibid. 112, 2843.CrossRefGoogle Scholar
  24. (b) Tilset, M. (1992) One-Electron Oxidation of Cyclopentadienylchromium Carbonyl Hydrides: Thermodynamics of Oxidative Activation of Metal-Hydrogen Bonds toward Homolytic and Heterolytic Cleavage, J. Am. Chem. Soc. 114, 2740–2741.CrossRefGoogle Scholar
  25. (c) Skagestad, V. and Tilset, M. (1993) Thermodynamics of Heterolytic and Homolytic M-H Bond Cleavage Reactions of 18-Electron and 17-Electron Group 6 Hydridotris(pyrazolyl)borate Metal Hydrides, J. Am. Chem. Soc. 115, 5077–5083.CrossRefGoogle Scholar
  26. (d) Pedersen, A., Skagestad, V., and Tilset, M. (1995) Thermodynamic Acidities and Homolytic Metal-Hydrogen Bond Energies of Group 8 Protonated Decamethylmetallocenes Cp*2MH+ (M = Ru, Os), Acta Chem. Scand. 49, 632–635.CrossRefGoogle Scholar
  27. [12]
    (a) Curtis, M. D. and Shiu, K.-B. (1985) Synthesis, Structure, and Fluxional Behavior of 7-Coordinate Complexes: TpMo(CO)3X (X = H, Br, I; Tp = Hydridotripyrazolylborato), Inorg. Chem. 24, 1213–1218.CrossRefGoogle Scholar
  28. (b) Curtis, M. D., Shiu, K.-B., Butler, W. M., and Huffman, J. C. (1986) Syntheses, Structures, and Molecular Orbital Analysis of Hydridotris(pyrazolyl)borate (Tp) Molybdenum Carbonyls: Paramagnetic TpMo(CO)3 and Triply Bonded Tp2Mo2(CO)4 (Mo≡Mo), J. Am. Chem. Soc. 108, 3335–3343.CrossRefGoogle Scholar
  29. [13]
    Angelici, R. J. (1995) Basicities of Transition Metal Complexes from Studies of Their Heats of Protonation: A Guide to Complex Reactivity, Acc. Chem. Res. 28, 51–60.CrossRefGoogle Scholar
  30. [14]
    Wang, D. and Angelici, R. J. (1996) Metal-Hydrogen Bond Dissociation Enthalpies in Series of Complexes of Eight Different Transition Metals, J. Am. Chem. Soc. 118, 936–942.Google Scholar
  31. [15]
    (a) Cappellani, E. P., Drouin, S. D., Jia, G., Maltby, P. A., Morris, R. H., and Schweitzer, C. T. (1994) Effect of the Ligand and Metal on the pK a Values of the Dihydrogen Ligand in the Series of Complexes [M(H2)H(L)2]+, M = Fe, Ru, Os, Containing Isosteric Ditertiaryphosphine Ligands, L, J. Am. Chem. Soc. 116, 3375–3388.CrossRefGoogle Scholar
  32. (b) Chin, B., Lough, A. J., Morris, R. H., Schweitzer, C. T., and D’Agostino, C. (1994) Influence of Chloride versus Hydride on H-H Bonding and Acidity of the Trans Dihydrogen Ligand in the Complexes trans-[Ru(H2)X(PR2CH2CH2PR2)2]+, X = Cl, H, R = Ph, Et. Crystal Structure Determinations of [RuCl(dppe)2]PF6 and trans-[Ru(H2)Cl(dppe)2]PF6, Inorg. Chem. 33, 6278–6288.CrossRefGoogle Scholar
  33. (c) Schlaf, M., Lough, A. J., Maltby, P. A., and Morris, R. H. (1996) Synthesis, Structure, and Properties of the Stable and Highly Acidic Dihydrogen Complex trans-[Os(ν2-H2)(CH3CN)(dppe)2](BF4)2. Perspectives on the Influence of the trans Ligand on the Chemistry of the Dihydrogen Ligand, Organometallics 15, 2270–2278.CrossRefGoogle Scholar
  34. [16]
    Trujillo, H. A., Casado, C. M., and Astruc, D. (1995) Thermodynamics of Benzylic C-H Activation in 18-and 19-Electron Iron Sandwich Complexes: Determination of pK a Values and Bond Dissociation Energies, J. Chem. Soc., Chem. Commun. 7–8.Google Scholar
  35. [17]
    Kerr, M. E., Zhang, X.-M., and Bruno, J. W. (1997) Effects of the Niobium(V) Center on the Energetics of Ligand-Centered Proton and Hydrogen Atom Transfer Reactions in Acyl and Alkoxide Complexes, Organometallics 16, 3249–3251.CrossRefGoogle Scholar
  36. [18]
    Ryan, O. B., Tilset, M., and Parker, V. D. (1990) Chemical and Electrochemical Oxidation of Group 6 Cyclopentadienylmetal Hydrides. First Estimation of 17-Electron Metal Hydride Cation Radical Thermodynamic Acidities and Their Decomposition to 17-Electron Neutral Radicals, J. Am. Chem. Soc. 112, 2618–2626.CrossRefGoogle Scholar
  37. [19]
    Kolthoff, I. M. and Chantooni, M. K. Jr. (1972) A Critical Study Involving Water, Methanol, Acetonitrile, N,N-Dimethylformamide, and Dimethyl Sulfoxide of Medium Ion Activity Coefficients, γ, on the Basis of the \({\gamma _{AsPh{4^ + } = }}{\gamma _{BPh{4^ - }}}\) Assumption, J. Phys. Chem. 76, 2024–2034.CrossRefGoogle Scholar
  38. [20]
    (a) Ryan, O. B., Tilset, M., and Parker, V. D. (1991) Oxidation of Ruthenium Hydride (η5-C5H5)Ru(CO)(PPh3)H: Generation of a Dihydrogen Complex by Oxidatively Induced Intermolecular Proton Transfer, Organometallics 10, 298–304.CrossRefGoogle Scholar
  39. (b) Ryan, O. B. and Tilset, M. (1991) Oxidation of CpRu(CO)(PMe3)H by 2/3, 1, and 2 Electrons by the Judicious Choice of Reaction Conditions. Generation of a Bridging Hydride via the Reaction between a 17-Electron Metal Hydride Cation Radical and its Conjugate Base, J. Am. Chem. Soc. 113, 9554–9561.CrossRefGoogle Scholar
  40. (c) Smith, K.-T. and Tilset, M. (1992) Oxidation of the Molybdenum Hydride CpMo(CO)2(PPh3)H. Syntheses of Cis and Trans CpMo(CO)2(PPh3)(NCMe)+ and the Kinetics of their Isomerization, J. Organomet. Chem. 431, 55–64.CrossRefGoogle Scholar
  41. (d) Tilset, M., Zlota, A., and Caulton, K. G. (1993) Attempted Oxidative Generation of a Dihydrogen Complex, Inorg. Chem. 32, 3816–3821.CrossRefGoogle Scholar
  42. (e) Smith, K.-T., Rømming, C., and Tilset, M. (1993) An Unexpected Disproportionation Mechanism for Proton-Transfer Reactions between 17-Electron Metal Hydride Cation Radicals and Neutral 18-Electron Metal Hydrides, J. Am. Chem. Soc. 115, 8681–8689.CrossRefGoogle Scholar
  43. (f) Smith, K.-T., Tilset, M., Kuhlman, R., and Caulton, K. G. (1995) Reactions of (PiPr3)2OsH6 Involving Addition of Protons and Removal of Electrons. Characterization of (1992) (PiPr3)2Os(NCMe)xHyz+ (x = 0,2,3; y = 1,2,3,4,7; z = 1,2), Including Dicationic η2-H2 Complexes, J. Am. Chem. Soc. 117, 9473–9480.CrossRefGoogle Scholar
  44. (g) Smith, K.-T., Tilset, M., Kristjánsdóttir, S. S, and Norton, J. R. (1995) Kinetic Isotope Effects on Metal to Nitrogen Proton Transfers, Inorg. Chem. 34, 6497–6504.CrossRefGoogle Scholar
  45. [21]
    For recent reviews on 17/19-electron equilibria, see: (a) Tyler, D. R. and Mao, F. (1990) Mechanistic Studies of Nineteen-Electron Organometallic Complexes; Synthesis of Stable Nineteen-Electron Complexes, Coord. Chem. Rev. 97, 119–140.CrossRefGoogle Scholar
  46. (b) Trogler, W. C. Ed. (1990) Organometallic Radical Processes, Elsevier, Amsterdam.Google Scholar
  47. (c) Astruc, D. (1991) Transition-Metal Radicals: Chameleon Structure and Catalytic Function, Acc. Chem. Res. 24, 36–42.CrossRefGoogle Scholar
  48. (d) Tyler, D. R. (1991) 19-Electron Organometallic Adducts, Acc. Chem. Res. 24, 325–331.CrossRefGoogle Scholar
  49. [22]
    (a) Tilset, M. (1994) Oxidation of CpM(CO)3 · and CpM(CO)3(NCMe)· (M = Cr, Mo, W): Kinetic and Thermodynamic Considerations of their Possible Involvement as Reducing Agents. Relative Acetonitrile Affinities of CpM(CO)3 + and CpM(CO)3 ·, Inorg. Chem. 33, 3121–3126.CrossRefGoogle Scholar
  50. (b) Zoski, C. G., Sweigart, D. A., Stone, N. J., Rieger, P. H, Mocellin, E., Mann, T. F., Mann, D. R, Gosser, D. K., Doeff, M. M., and Bond, A. M. (1988) An Electrochemical Study of the Substitution and Decomposition Reactions of (Arene)tricarbonylchromium Radical Cations, J. Am. Chem. Soc. 110, 2109–2116.CrossRefGoogle Scholar
  51. (c) Zhang, Y., Gosser, D. K., Rieger, P. H., and Sweigart, D. A. (1991) Reactivity of 17-, 18-, and 19-Electron Cationic Complexes Generated by the Electrochemical Oxidation of Tricarbonyl(mesitylene)tungsten, J. Am. Chem. Soc. 113, 4062–4068.CrossRefGoogle Scholar
  52. [23]
    Tilset, M., Hamon, J.-R., and Hamon, P. (1998) Relative M-X Bond Dissociation Energies in 16-, 17-and 18-Electron Organotransition-Metal Complexes (X = Halide, H), Chem. Commun. 765–766.Google Scholar
  53. [24]
    Wayner, D. D. M., McPhee, D. J., and Griller, D. (1988) Oxidation and Reduction Potentials of Transient Free Radicals, J. Am. Chem. Soc. 110, 132–137.CrossRefGoogle Scholar
  54. [25]
    See references cited in Flowers, R. A. II, Ludwig, R. T., Meckhof, A., and Walek, S. (1995) Thermodynamics for C-H Bond-Breaking of Some Amphihydric Compounds by Transfer of Protons, Hydride Ions, H-Atoms and Electrons, Pure Appl. Chem. 67, 729–734 [3].CrossRefGoogle Scholar
  55. [26]
    (a) Caulton, K. G. (1994) The Influence of π-Stabilized Unsaturation and Filled/Filled Repulsions in Transition Metal Chemistry, New J. Chem. 18, 25–41.Google Scholar
  56. (b) Doherty, N. M. and Hoffman, N. W. (1991) Transition-Metal Fluoro Compounds Containing Carbonyl, Phosphine, Arsine, and Stibine Ligands, Chem. Rev. 91, 553–573.CrossRefGoogle Scholar
  57. [27]
    (a) Roger, C., Hamon, P., Toupet, L., Rabaâ, H., Saillard, J.-Y., Hamon, J.-R., and Lapinte, C. (1991) Halo-and Alkyl(pentamethylcyclopentadienyl)(1,2-bis(diphenylphosphino)ethane)iron(III) 17-Electron Complexes: Synthesis, NMR and Magnetic Properties, and EHMO Calculations, Organometallics 10, 1045–1054.CrossRefGoogle Scholar
  58. (b) Hamon, P, Toupet, L., Hamon, J.-R, and Lapinte, C. (1992) Novel Diamagnetic and Paramagnetic Iron(II), Iron(III), and Iron(IV) Classical and Nonclassical Hydrides. X-ray Crystal Structure of [Fe(C5Me5)(dppe)D]PF6, Organometallics 11, 1429–1431.CrossRefGoogle Scholar
  59. (c) Hamon, P, Hamon, J.-R., and Lapinte, C. (1992) Isolation and Characterization of a Cationic 19-Electron Iron(III) Hydride Complex; Electron Transfer Induced Hydride Migration by Carbon Monoxide at an Iron(III) Centre, J. Chem. Soc., Chem. Commun. 1602–1603.Google Scholar
  60. (d) Hamon, P, Toupet, L, Hamon, J.-R, and Lapinte, C. (1996) Syntheses and X-ray Crystal Structures of Five-and Six-Coordinated Iron(I) and Iron(II) Complexes with the Same (η5-C5Me5)Fe(dppe) Framework, Organometallics 15, 10–12.CrossRefGoogle Scholar
  61. [28]
    (a) Sharp, P. and Frank, K. G. (1985) Reactions of WCl2L4 (L = a Phosphine). 2. Tungsten(IV) and Tungsten(V) Hydride Complexes, Inorg. Chem. 24, 1808–1813.CrossRefGoogle Scholar
  62. (b) Pleune, B., Poli, R, and Fettinger, J. C. (1998) Synthesis and Structure of the Stable Paramagnetic Cyclopentadienyl Polyhydride Complexes [Cp*MH3(dppe)]+ (M = Mo, W): Stronger M-H Bonds upon Oxidation, J. Am. Chem. Soc. 120, 3257–3258.CrossRefGoogle Scholar
  63. [29]
    (a) Pedersen, A. and Tilset, M. (1993) Oxidatively Induced Reductive Eliminations. Kinetics and Mechanism of the Elimination of Ethane from the 17-Electron Cation Radical of Cp*Rh(PPh3)(CH3)2, Organometallics 12, 56–64.CrossRefGoogle Scholar
  64. (b) Pedersen, A. and Tilset, M. (1994) A Comparative Study of the Oxidation Chemistry of the Iridium Dihydride, Hydrido Methyl, and Dimethyl Complexes Cp*Ir(PPh3)(R)(R′) (R/R′ = H/H, H/Me, Me/Me), Organometallics 13, 4887–4894.CrossRefGoogle Scholar
  65. (c) Fooladi, E. and Tilset, M. (1997) Oxidatively Induced Reductive Eliminations. A Mechanistic Study of the Oxidation Chemistry of CnRhMe3 (Cn = 1,4,7-trimethyl-1,4,7-triazacyclononane), Inorg. Chem. 36, 6021–6027.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1999

Authors and Affiliations

  • Mats Tilset
    • 1
  1. 1.Department of ChemistryUniversity of OsloOsloNorway

Personalised recommendations