The F19 chemical shifts of m- and p-fluorotoluene -alpha, alpha, alpha-d3 and their nondeuterated analogs were determined. No appreciable isotope effect was detected for the meta isomer; however, the chemical shift of p-fluorotoluene-alpha, alpha, alpha-d3 was found to be about 0.7 c.p.s. less than that of p-fluorotoluene. These results imply negligible or zero inductive isotope effects of the methyl group, but a small resonance isotope effect in the direction expected from recent results on secondary deuterium isotope effects in kinetic and equilibrium studies.

Project 7903. AD627875. "Reprinted from the Journal of the American Chemical Society, 87, 4917 (1965)."