Fluorine-Based Crystal Engineering

Hybrid compounds R F -X-R H consisting of perfluoro and hydro moieties, R F and R H , which are connected with X functionality, are described. New crystal engineering based on these hybrid compounds is proposed as a rational method for the design of the functional materials. Hexafluoropropene trimers are selected as the fluoro synthons. A systematic investigation on the crystal structures of the hybrid compounds revealed that there are five packing motifs in connection with the topology of the molecules. Topochemical requirements for the solid-state polymerization of diacetylene functionality were satisfied with the precise tuning by tailor-made hybrid synthons. As a result, a black crystalline material with a metallic luster was synthesized. This new fluorine-based crystal engineering will be one of the unique molecular design methods for the material science.