Crystal structural change by guest sorption/release processes of the macrocyclic boronic ester

Abstract

from powder diffraction data. Glycyl-L-tyrosine is known to crystallize as dihydrate from an aqueous-methanol solution [1]. Recently, we obtained the trihydrate from an aqueous solution, and carried out single-crystal structure analysis [2]. Humidity-and temperature-dependent phase transitions of both hydrates were examined by powder X-ray diffraction analysis. The dihydrate is stable at room temperature in the relative humidity (rh) range from 80% to 0% and the structural transition proceeds around 50 °C at 0% rh. On the other hand, the trihydrate loses a part of crystal water at 0% rh, and further dehydrates around 80 °C. At the first step, we have successfully determined the crystal structure of the dihydrate from powder diffraction data. The structure coincides with that determined by singlecrystal structure analysis. In addition the cell parameters of the partly dehydrated state of the trihydrate at 0% rh have been determined and structure analysis from powder diffraction data is in progress.