Selective inversion investigations of slow molecular motion in solid state deuteron NMR spectroscopy

Deuteron selective inversion experiments are reported for polycrystalline dimethyl sulfone-d(6) as a function of temperature from 288 to 333 K. Double sideband modulation was used to achieve efficient off-resonance orientation-selective inversion. Fitting the selective inversion-recovery curves to two-site jump equations yields the motional rate. Temperature dependent jump rates, obtained from both selective inversion and deuteron quadrupole echo lineshapes, give an activation energy E(a) = 86.5 +/- 1.4 kJ mol(-1) and a frequency factor In(A)= 39.2 +/- 0.5. These values differ significantly from those of earlier C-13 lineshape studies. At 298 K, variable power excitation was used to determine the underlying orientation dependent homogeneous linewidth, which is predominantly dipolar. The temperature dependence of the homogeneous linewidth is a sensitive indicator of large angle jump motion in the range 10(3)-10(4) s(-1).