Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Chemistry and Pharmacology
Crystals of the title complex, C28H36N4·C2H6OS, undergo a phase transition between room temperature and 198 K, as determined by X-ray diffraction techniques. A monoclinic form is observed at room temperature, while a triclinic modification is found at 198 K, with Z′ changing from 1 to 2. Differential scanning calorimetry (DSC) of the calixpyrrole–dimethyl sulfoxide complex revealed a series of phase changes between 273 and 243 K. The transition from the room-temperature monoclinic form to the low-temperature triclinic form is reversible, as determined by changes in the cell dimensions from remeasuring selected reflections at room temperature and at temperatures below 223 K. The uncomplexed calixpyrrole molecule shows no phase changes occurring between room temperature and 233 K, the low-temperature limit of the DSC.
Type of Medium: