Trichloromethyl peroxy radical

A one-electron reduction of the bond between an aliphatic carbon and a halogen leads to a halogen anion and a carbon-free radical. A good example is the reduction of carbon tetrachloride as discussed earlier in this chapter. The first product in the reduction is the trichloromethyl-free radical. Carbon-centered radicals are not very reactive with biological molecules, but they react very rapidly with molecular oxygen (a diradical) to form a peroxy-free radical (Fig. 5.15), which is quite toxic (10). 

It is clear from Table III that addition of methyl radicals occurs 1.5 to 3 times as often as abstraction, while for the peroxy radical addition occurs only 0.1 to 2 times as often. Despite this large variation in the proportions reacting by addition, the relative rates of addition of these two radicals to cyclic olefins are about the same. In fact, the reactivity of cyclohexene relative to cyclopentene in these systems agrees with that observed (25) for the trichloromethyl radical (0.14 to 0.30). However,... 

The mechanism of carbon tetrachloride nephrotoxicity involves the initial homolytic cleavage of carbon tetrachloride by cytochrome P450 to form the trichloromethyl and chlorine free radicals (Figure 6). The trichloromethyl free radical can then alkylate renal macromolecules or interact with membrane unsaturated fatty acids to initiate lipid peroxidation. The trichloromethyl free radical may also combine with molecular oxygen to form a peroxy free radical that is more reactive than the trichloromethyl free... 

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