FACTORS AFFECTING THE FORMATION IN THE SOLID-STATE OF THE METASTABLE COMPLEX BETWEEN NAPHTHALENE AND DIMETHYL-BETA-CYCLODEXTRIN

An equimolar mixture of naphthalene and amorphous heptakis-(2,6-di-O-m ethyl)-beta-cyclodextrin (DM beta CD) was heated at 70 or 90 degrees C in a sealed container, After heating for 15 min at 90 degrees C, the mixture was crystallized to show an excimer fluorescence of naphthalen e, and the fluorescence spectrum changed to a monomer emission by furt her prolongation of heating time, accompanied by a slight change in it s powder X-ray diffractogram. It is suggested that a metastable comple x showing the excimer emission of naphthalene was transformed to a sta ble complex showing the monomer emission. The mixing molar ratio of na phthalene to DM beta CD was also found to affect the transformation te mperature of the complex.