Vapochromism associated with the changes in the molecular arrangement of organic crystalsElectronic supplementary information (ESI) available: Experimental details, TG-DTA, PXRD and crystallographic data. CCDC 1006003-1006005. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ce01314j

• Main Authors: Yamada, Shinji, Katsuki, Ayaka, Nojiri, Yuka, Tokugawa, Yoko
• Format: Article
• Language: English
• ISSN: 1466-8033
• DOI: 10.1039/c4ce01314j

Exposure of the yellow anhydrate crystals of 4′-alkoxy-4-azachalcones to water vapor gave red hydrate crystals. On the other hand, dehydration of the hydrate phase by heating recovered the anhydrate yellow phase. A comparison of the crystal structures of the anhydrate and hydrate crystals confirmed that the molecular arrangement is significantly changed during the hydration-dehydration processes: the changes in the orientation mode from head-to-tail to head-to-head and the displacement of chloride ions and water molecules are involved in the crystal transformations. PXRD studies clarified the reversibility of the crystal transformations occurring in the hydration-dehydration processes. Exposure of yellow anhydrate organic crystals to water vapor gave red hydrate crystals with significant changes in the molecular arrangement.