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 contants in dimethoxyethane at 195 K for electron transfer between perdeuteriated p‐xylene and xylene, α‐d3‐p‐xylene and α,α′‐d6‐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 l mol−1 per deuterium, whereas ring deuteriation in these systems lowers the solution EA by about 370 J l 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.