Formation of superoxo complexes

In the case of many metalloporphyrin derivatives, steric hindrance prevents the formation of p-peroxodimetal species therefore, it is possible to measure the rate of formation and decomposition of side-on superoxo complexes. The stopped-flow technique has been widely utilized. Gibson s relaxation type method [301] has proved to be very [301] convenient for heme complexes. It is based on the fact that 0  

which now binds both 0 and CO in a ratio determined by the rate 

Spectrophotometrie monitoring of the fast and slow phases provides all the rate constants involved in equations (33). Some typical values are listed in Table XVIII. 

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