Some Effects of the Sixth Ligand on the Electron Spin Resonance Spectra of Pentacoordinated Low-Spin Co(II) Complexes

  • Hideo Kon
  • Nobuko Kataoka


Assignment of the ESR spectra was made for a low-spin pentacoordinated Co(II) complex, CoII(phenylisocyanide)5(C1O4)2, and its hydrated form, in which the sixth coordination site is occupied by a water molecule. It was shown that the occurrence in the frozen state of each form, anhydrous or hydrated, is determined by the solvent, i.e., by whether a hydrophobic or hydrophilic solvent is used. Based upon the assignment, the effect of attaching the sixth ligand on the ESR parameters was examined. It was pointed out that the effect is to shift one of the g components toward a higher value and the 59Co isotropic contact term toward a more negative value. This conclusion was corroborated by examining the ESR parameters of the tetrakis and hexakis (phenylisocyanide) complexes. A brief explanation was given in terms of vibronic mixing of \({{d}_{{{x}^{2}}-{{y}^{2}}}}\) into \({{d}_{{{z}^{2}}}}\).


Electron Spin Resonance Spectrum Hydrated Form Vibronic Interaction Anhydrous Form Hydrophobic Solvent 
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  1. 1.
    J. J. Alexander and H. B. Gray, J. Am. Chem. Soc. 89, 3356 (1967).CrossRefGoogle Scholar
  2. 2.
    A. Sacco, Gazz. Chim. Ital. 84, 370 (1954).Google Scholar
  3. 3.
    J. M. Pratt and P. R. Silverman, Chem. Comm. 1967, 117; J. Chem. Soc. (A) 1967, 1286.Google Scholar
  4. 4.
    N. Kataoka and H. Kon, J. Am. Chem. Soc. 90, 2978 (1968).CrossRefGoogle Scholar
  5. 5.
    H. Kon, Spectry. Letters 1, 49 (1968).CrossRefGoogle Scholar
  6. 6.
    L. Malatesta and A. Sacco, Gazz. Chim. Ital. 83, 499 (1953).Google Scholar
  7. 7.
    A. Cotton, T. G. Dunne, and J. S. Wood, Inorg. Chem. 4, 318 (1965).CrossRefGoogle Scholar
  8. 8.
    J. M. Assour, J. Am. Chem. Soc. 87, 4701 (1965).CrossRefGoogle Scholar
  9. 9.
    M. C. M. O’Brien, Proc. Roy. Soc. (London) A281, 323 (1964).CrossRefGoogle Scholar
  10. 10.
    N. Kataoka and H.Kon, to be published in J. Phys. Chem. Google Scholar
  11. 11.
    B. R. McGarvey, J. Phys. Chem. 71, 51 (1967).CrossRefGoogle Scholar
  12. 12.
    J. M. Pratt and P. R. Silverman, J. Chem. Soc. (A), p. 1291 (1967).Google Scholar

Copyright information

© Plenum Press, New York 1969

Authors and Affiliations

  • Hideo Kon
    • 1
  • Nobuko Kataoka
    • 1
  1. 1.Laboratory of Physical BiologyNational Institute of Arthritis and Metabolic DiseasesBethesdaUSA

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