Catalytic oxidations using cobalt(II) complexes - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 299

The kinetics and mechanism of the oxidation of 2-aminophenol (ap) to
2-aminophenoxazin-3-one (apx) under ambient conditions, catalyzed by the
recently synthesized tetrakis(3,5-di- tert -butyl-4-hydroxyphenyl)-dodeca-
chlorophthalocyaninatocobalt(II), (Figure 41) have been studied
by spectrophotometry 128,129 . The rate of ap formation is first-order in
and obeys Michaelis-Menten type kinetics with respect to [ap].
The suggested mechanism involves rate-determining inner-sphere electron
transfer from coordinated ap to coordinated in the superoxo complex.
Cobalt(II)-phthalocyanine [Co(II)pc] supported on active carbon exhibits
catalytic activity in the oxidation of sulfide ions to elemental sulfur by
dioxygen in aqueous solution 131 . Hydrophobization of the carbon surface
facilitates activation of dioxygen by adsorption. Sulfide ion activation occurs
mainly on the supported Co(II)Pc.
Water soluble cobalt(II) 2,9,16,23-tetrasulfophthalocyanine, zinc(II)-
2,9,16,23-tetrasulfo-phthalocyanine, zinc(II)tetracarboxyphthalocyanine, and
non-metallic sulfophthalocyanine complexes are catalysts and photocatalysts
for the oxidation of sulfide, sulfite and thiosulfate ions by dioxygen 132 .
Typical conditions are 293 K, 1 atm and pH 9.24 in aqueous solution.The
cobalt phthalocyanine complexes show high catalytic activity only in the