PROTON SPIN RELAXATION AND METHYL AND HYDROXY GROUP MOTION

Proton spin-lattice relaxation rates R = T1-1 have been measured in powdered samples of 4-methyl-2,6-di-tertiarybutyl phenol between 77 and 170 K. Deuteration of the hydroxy proton leads to a large change in R in the vicinity of the 120-K R maximum and in the high-temperature region. The data are successfully, although probably not uniquely, fitted and the interpretation suggests that in addition to the motion of the hydroxy proton playing a significant role in the relaxation, the two pairs of t-butyl methyl groups also contributing are inequivalent. The departure, at low temperatures, from an ω-2 dependence of R where ω is the nuclear Larmor angular frequency is also investigated. © 1979.