SOLUTION ELECTRON-AFFINITY CHANGES VIA THE DEUTERIATION OF THE METHYL-GROUPS OF P-XYLENE

EPR techniques, including spectral double integration, were utilized t o measure the equilibrium constants in dimethoxyethane at 195 K For el ectron transfer between perdeuteriated p-xylene and xylene, alpha-d(3) -p-xylene and alpha,alpha'-d(6)-p-xylene. The results, coupled with th e law of Hess, yield all the relative solution electron affinities (EA ), It was found that methyl deuteriation lowers the solution EA by 160 J\mol(-1) per deuterium, whereas ring deuteriation in these systems l owers the solution EA by about 370 J\mol(-1) per deuterium, which is a bout the same effect as is observed in the benzene system, The results are discussed in terms of hyperconjugative, inductive and solvation e ffects.