A sample of 1-La with an internal standard of 1,3,5-tri-tert-butylbenzene was dissolved in neat C4D8O in an effort to reduce sample decomposition prior to collection of NMR spectra and to investigate THF exchange dynamics further. However, this did not provide NMR data that were easier to interpret than those obtained for the 9 : 1 C6D6 : C4D8O solution due to the complex exchange behavior, thus we did not extend this study to C4D8O solutions of paramagnetic Pr and 1-Nd that may arise from THF, but we do not assign them as their identity is uncertain due to sample decomposition and complex exchange equilibria. The lower gyromagnetic ratio of C nuclei in combination with the generally short relaxation times in these samples precluded the assignment of THF signals via correlation experiments.