II polyamine chelates

Another group of cobalt(11) complexes that show catalytic activity in 2,6-DTBP oxidation to the corresponding BQ and DPQ has been described by Bedell and Martell [56]. They are 1 1 Co(II) polyamine chelates (with the ligands listed below), some of which form monobridged p-peroxo complexes with dioxygen, whereas others afford dibridged (p-peroxo)(p-hydroxo) derivatives with the ligands listed in Table II. 

Stabilities of cobalt-dioxygen complexes with the ligands (L) listed 

The kinetic laws for the disappearance of DTBP and for product formation, as determined by gas chromatographic analysis, have the form  

This is similar to a classical reaction assumed to occur in hydrocarbon autoxidations [58], which may be reversible with highly resonance-stabilized radicals such as di-t-butylphenoxyl [59]. The 

The problem with this mechanism is that the first-order dependence on the 2,6-DTBP concentration is not explained, unless reversible H-atom abstraction is assumed. 

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