Studies on Grignard reagents. Part III. Proton resonance spectra of alkyl and aryl Grignard reagents

Proton resonance spectra are reported for a variety of Grignard reagents in a number of different solvents, and also for mixtures with the corresponding bis-alkyl-and-aryl-magnesiums. At low temperatures chemical exchange of alkyl or aryl groups is slow on a proton resonance time-scale. The position of the Schlenk equilibrium, for which quantitative data are presented, depends very markedly on the alkyl or aryl group and on the solvent. Alkyl or aryl exchange is slower in strongly co-ordinating solvents.