When the strength of the paramagnetic interaction is nonnegligible,
the conventional 2H NMR method for diamagnetic
solids needs to be modified for paramagnetic solids. In NMR
experiments, the usual quadrupole-echo (QE) sequence [37] for
the measurement of wideline 2H NMR spectra of static samples
yields unwanted phase distortion of the NMR signals in paramagnetic
solids. The remedy is to use improved echo sequences
that include additional 180 pulses [38] or select an appropriate
coherence transfer pathway [39], to exclude the effects of
the paramagnetic shift interactions. The QCPMG sequence for
enhancement of sensitivity should also be altered for paramagnetic
compounds
so small, trifling, or unimportant that it may safely be neglected or disregarded:
The extra expenses were negligible.