Cocrystals Definitions

Abstract

Cocrystals may be stabilized by different types of interactions, besides that of hydrogen bonding—the only type of stabilization specified in the current definitions. There are, for instance, van der Waals forces, π–π interactions, and halogen bonding, among others. The current definitions of cocrystals do not describe these types of interactions, which may be crucial in determining cocrystal formation in diverse compounds. Herein, we attempt to propose a more universal definition of cocrystals, considering all of the various forces involved, and to place more emphasis on the characterization of cocrystals. Moreover, we highlight some examples of cocrystals that are very clearly stabilized by forces other than hydrogen bonds.

Keywords:

• Cocrystals
• Synthons
• Heterosynthons
• Hydrogen bond
• Halogen binding

Acknowledgements

F. Lara-Ochoa gratefully acknowledges Laboratorios Silanes for their sponsoring and support of the travel expenses and registration fee to the conference Polymorphism & Crystallisation 2007, and to Edith Lara-Moreno for her invaluable help in the manuscript elaboration.