Natural abundance carbon‐13 and deuterium NMR studies on the liquid and solid phases oftert‐butyl chloride andtert‐butyl nitrate

Abstract

AbstractNMR line widths (13C) and spin–lattice relaxation times (13C and2H) were measured over a wide temperature region in liquid and solidtert‐butyl chloride (1) andtert‐butyl nitrate (2). Molecular self‐diffusion, with activation energies in the range 29–37 kJ mol−1, is responsible for the considerable line narrowing observed for the13C resonances in solid I of these substances.An analysis of the13C and2H spin–lattice relaxation times (T1) in the liquid and solid phases of 1 and 2 is reported. Rotational correlation times, activation energies and pre‐exponential factors for the appropriate motions were obtained from the Arrhenius equation. The13C and2HT1data suggest that the overall reorientation occurring in solid I of 1 and 2 is slightly retarded by the melting process. The13CT1data show that the faster motion in the ordered phases of 1 and 2 is the uniaxialC3′ reorientation with an activation energy of 12–14 kJ mol−1, while the slower motion is theC3methyl reorientation with an activation energy of 12–13 kJ mol−1.