We report several aspects of the characterization of a material (triacetylated-β-cyclodextrin) that exists in two crystalline polymorphic forms (denoted I and II). A striking feature of this polymorphic system is that polymorph I (MPt 194 °C) and polymorph II (MPt 219 °C) exhibit remarkably different solubility in the fluorinated solvent 2H,3H-decafluoropentane, with the solubility higher by a factor of ca. eight for polymorph I at ambient temperature. Structural information established from powder X-ray diffraction and high-resolution solid-state 13C NMR spectroscopy for polymorphs I and II is reported, including crystal structure determination of polymorph II from the powder X-ray diffraction data. Differential scanning calorimetry and high-temperature powder X-ray diffraction demonstrate that the metastable polymorph I converts to the stable polymorph II over a range of elevated temperatures. The combined evidence of these and other techniques suggests that there is a monotropic relationship between polymorphs I and II.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.