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

EPR techniques, including spectral double integration, were utilized to measure the equilibrium constants in dimethoxyethane at 195 K For electron transfer between perdeuteriated p-xylene and xylene, alpha-d(3)-p-xylene and alpha,alpha'-d(6)-p-xylene. The results, coupled with the 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 lowers the solution EA by about 370 J\mol(-1) per deuterium, which is about the same effect as is observed in the benzene system, The results are discussed in terms of hyperconjugative, inductive and solvation effects.