Electron spin resonance studies. Part XX. The generation of organic radicals by the one-electron reduction of aliphatic halogeno-compounds in aqueous solution

The carbon dioxide radical-anion, which can be obtained in aqueous solution through the oxidation of sodium formate by the hydroxyl radical produced from titanium(III) ion and hydrogen peroxide, is an effective one-electron reducing agent for many aliphatic halogeno-compounds; we have observed the e.s.r. spectra of a number of organic radicals formed in this way. The method seems to be generally applicable to iodo-compounds, but with bromo- or chloro-compounds there is a requirement for a substituent which is capable of stabilising the resulting radical. The conjugate acid of the carbon dioxide radical-anion is a somewhat less effective reducing agent, and the radical ·CMe2OH is even less effective.