Russian Chemical Bulletin

, Volume 42, Issue 6, pp 981–985

Redox properties of cobalt(II) and methylcobalt(III) complexes with dianionic macrocyclic polychelate ligands

Authors

  • Yu. E. Kovalenko
    • L. V. Pisarzhevskii Institute of Physical ChemistryUkrainian Academy of Sciences
  • Ya. D. Lampeka
    • L. V. Pisarzhevskii Institute of Physical ChemistryUkrainian Academy of Sciences
  • I. Ya. Levitin
    • L. V. Pisarzhevskii Institute of Physical ChemistryUkrainian Academy of Sciences
  • K. B. Yatsimirskii
    • L. V. Pisarzhevskii Institute of Physical ChemistryUkrainian Academy of Sciences
  • K. Muller
    • Chemical DepartmentSchiller University
  • D. Seidel
    • Chemical DepartmentSchiller University
  • E. -G. Jager
    • Chemical DepartmentSchiller University
General and Inorganic Chemistry

DOI: 10.1007/BF00704180

Cite this article as:
Kovalenko, Y.E., Lampeka, Y.D., Levitin, I.Y. et al. Russ Chem Bull (1993) 42: 981. doi:10.1007/BF00704180

Abstract

Redox potentials of a series of complexes of cobalt(II) and organocobalt(III) with tetraazamacrocyclic (N4) and N2O2-noncyclic polychelate ligands have been determined by cyclic voltammetry. Introduction of ano-phenylene fragment instead of an ethylene fragment into an equatorial ligand and/or exchange of an N4-coordination chromophore for the N2O2-analog has been shown to result in the anodic shift of redox potentials of MeCo(IV)L/ MeCo(III)L, MeCo(III)L/MeCo(II)L, and Co(II)L/Co(I)L pairs. It has been established that the solvent effect on redox potential is larger for Co(III)L/Co(II)L than for other pairs. Apparently, this is the first case when quasi-reversible stages of oxidation of MeCo(III)L to MeCo(IV)L+ and MeCo(IV)L+ to [MeCo(IV)L]2+ can be simultaneously observed. A. relatively stable complex of methylcobalt(IV) with a long lifetime at ∼20 °C has been registered by the ESR method.

Key words

organometallic compounds cobalt—carbon bond redox potentials cobalt(IV)

Copyright information

© Plenum Publishing Corporation 1994