Crystallisation of organic hydrates by sublimation

A series of five organic molecules with known crystalline hydrates were sublimed under vacuum in the presence and absence of water. In two systems, crystals of the hydrate could easily be grown from sublimation. Generally, a mixture of hydrated and anhydrous forms were obtained from sublimation. In several cases, an increase in the quantity of water added to the sublimation system resulted in an increase in water content of the sublimed crystals. Competition studies demonstrated that transfer of water can take place between hydrate and anhydrous forms during a sublimation experiment. Hydrates of organic molecules can be crystallised by sublimation if there is a strong hydrogen bond to water in the solid hydrate.

Automated summary

This study demonstrates that crystalline hydrates of organic molecules can be obtained through sublimation under vacuum. The crystals obtained from sublimation consist of both hydrated and anhydrous forms. Moreover, increasing the amount of water in the sublimation system results in a higher water content in the sublimed crystals. Competition studies show the transfer of water between hydrate and anhydrous forms during sublimation, indicating the presence of strong hydrogen bonds between water and the solid hydrate.