AN INVESTIGATION OF SOLID-STATE PHASE-TRANSITIONS IN 1-ADAMANTANOL AND 2-ADAMANTANOL BY C-13 CP-MAS NMR

High-resolution C-13 NMR spectra have been recorded in the solid state at various temperatures for 1- and 2-adamantanol using the CP-MAS technique. The C-13 chemical shifts for these compounds have been assigned based upon literature precedents. Because different regions of the samples experienced slightly different temperatures, it was possible to observe more than one species at a given nominal temperature. These have been ascribed to the co-existence of different solid state phases and the results obtained have been compared with earlier NMR and DTA findings. Given accurate DTA measurements of the transition temperatures for a range of substituted adamantanes, this provides a precise way of calibrating variable temperature CP-MAS experiments, revealing the temperature and any temperature inhomogeneities actually at the sample.