Linear and bent halogen-bonded architectures in cocrystals: Design, properties and mechanism of formation via grinding

ORGN 260

Tomislav Friscic, tf253@cam.ac.uk1, Dominik Cincic2, and William Jones1. (1) Pfizer Institute for Pharmaceutical Materials Science and Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, England, (2) Laboratory of General and Inorganic Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, Zagreb, HR-10000, Croatia
Multi-component molecular crystals (cocrystals) have recently been recognized suitable for the construction of functional solids, in particular pharmaceutical, electronic or optical materials, and have been utilized as tailor-made media for organic solid-state reactions. Such interest has inspired the exploration of new approaches for cocrystal synthesis and design. This contribution will delineate our experiences in using environmentally friendly mechanochemical methods (neat and liquid-assisted grinding) to construct halogen-bonded cocrystals. The halogen bond is becoming recognized as a viable alternative to the hydrogen bond in cocrystal design, and we present linear and zigzag halogen-bonded architectures constructed by solid-state grinding. We describe how solid-state properties of cocrystals can be controlled through manipulating the halogen bond strength, and provide a mechanism for mechanochemical cocrystal synthesis. The stepwise mechanism involves finite molecular assemblies as intermediates in the construction of halogen-bonded chains and results from the competition between strong (N...I) and weak (S...I) intermolecular interactions.

 

Molecular Recognition and Self Assembly
1:00 PM-4:40 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. R04, Oral

Division of Organic Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008