RESUMO
Carbon-13, deuterium and proton NMR line shapes of polycrystalline tert-butyl iodide (1) have been studied between 200 K and the melting point (239 K). Carbon-13 and deuterium spin-lattice relaxation times (T1 ) were measured between 313 and 200 K in the liquid and solid phases of 1. The NMR line shape data indicate the occurrence of two disordered phases of 1 between the melting point and 222 K. An analysis of the 13 C and 2 H T1 relaxation times is reported. The 13 C and 2 H T1 relaxation is governed by overall molecular tumbling in the liquid and disordered phases of 1, whereas the 13 C T1 relaxation in the ordered solid is governed by uniaxial molecular reorientation of the tert-butyl group. Rotational correlation times, activation energies and pre-exponential factors were obtained from the T1 data by using the Arrhenius equation. Significantly different activation parameters were obtained for the two disordered solids. The effective correlation time at the melting point of 1 (ca. 5 ps) is 2-3 times longer than for other globular tert-butyl compounds.
