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Kinetics of substitution in two water soluble cobalt(III)-porphyrins


Kinetics of substitution of thiocyanate and pyridine in the axial positions of tetra(p-trimethylammoniumphenyl)porphinatocobalt(III) and tetra(p-sulfonatophenyl)porphinato cobalt(III) were investigated at pH 4.00 and ionic strength 0.1 M (NaNO3) in aqueous solution. These reactions were found to be as facile as other such reactions of cobalt(III) porphyrins even though a new synthesis was employed in the present study. The rates of these reactions are proportional to the base strength of the parent free base porphyrin. Electrostatic attraction between the ligand and the porphyrin peripheral charges were also found to enhance the rates. The cause of labilization is believed to be primarily electronic and not steric.

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Correspondence to M. Krishnamurthy.

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Abwao-Konya, J., Cappelli, A., Jacobs, L. et al. Kinetics of substitution in two water soluble cobalt(III)-porphyrins. Transition Met Chem 9, 270–273 (1984).

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  • Physical Chemistry
  • Aqueous Solution
  • Cobalt
  • Inorganic Chemistry
  • Pyridine