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A Proton Spin-Lattice Relaxation Rate Study Of Methyl And T-Butyl Group Reorientation In The Solid State, Laura C. Popa, Arnold L. Rheingold, Peter A. Beckmann

Physics Faculty Research and Scholarship

We have measured the solid state nuclear magnetic resonance (NMR) ¹H spin-lattice relaxation rate from 93 to 340 K at NMR frequencies of 8.5 and 53 MHz in 5-t-butyl-4-hydroxy-2-methylphenyl sulfide. We have also determined the molecular and crystal structures from X-ray diffraction experiments. The relaxation is caused by methyl and t-butyl group rotation modulating the spin–spin interactions and we relate the NMR dynamical parameters to the structure. A successful fit of the data requires that the 2-methyl groups are rotating fast (on the NMR time scale) even at the lowest temperatures employed. The rotational barrier for …