Proton Magnetic Resonance Studies of Trimethylacetonitrile

Proton magnetic resonance studies of the second moment S of the absorption spectrum and the spin—lattice relaxation time T1 have been made over a wide temperature range in solid trimethylacetonitrile, (CH3)3CCN. The results indicate that the dominant molecular motion occurring in this compound is that of the t-butyl group about the C–CN axis coupled with rotation of the methyl groups about their C3 axes. The ``one-step'' nature of the change in S and the temperature dependence of T1 which is characterized by a single minimum indicate that the two types of motion involved must occur in such rapid succession as to produce effectively simultaneous influence on S and T1. The motion persists above 80°K and is associated with an activation energy E=3.9±0.2 kcal/mole.