On the usefulness of crown ethers in freezing out the intramolecular cation migration in radical ion pairs

The additon of stoichiometric amounts of dibenzo-18-crown-6 ether to solutions of the sodium ion pairs of pyrazine and therephthalonitrile has been found to reduce dramatically the rate constant for the intramolecular migration of the alkali cation. The proton and nitrogen hyperfine splitting in the slow exchange region, could be easily measured under these experimental conditions. © 1997.