Formation of a heptakis-(2,6-di-O-methyl)-β-cyclodextrin-p-nitrophenol inclusion compound by sealed-heating

The complexes of heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DMβCD) and p-nitrophenol (p-NP), which were prepared by sealed-heating and a slow evaporation method, were comparatively evaluated. From the results of differential scanning calorimetry, powder X-ray diffraction, and infrared spectroscopy, the sealed-heated sample was considered as a new complex which was different from the slow evaporation complex. Also, the data from a sublimation experiment indicated that the inhibition of sublimation of p-NP was observed only in the sealed-heated sample. These results suggested the p- NP molecules were included within the cavity of DMβCD molecules, whereas in case of the slow evaporation complex, p-NP molecules were located in the intermolecular space among the DMβCD molecules.