Chapter 2:Fluoroalkylated Styrene Dimers: Synthesis, Properties, and Applications

Head-to-head type styrene dimers bearing two fluoroalkyl end-groups were efficiently synthesized by a simple reaction of a perfluoroalkyl iodide with styrene under radical conditions as a mixture of meso and racemic (rac) forms. The dimer is an interesting compound as the smallest model unit for fluoroalkyl end-capped oligomers and polymers for investigating the role of fluoroalkyl groups in functional materials. The isomers could be separated from each other by column chromatography and/or recrystallization. The meso form of the dimer 1 gave a crystal suitable for X-ray diffraction study and the crystal structure was found to be based on π,π-stacking of benzene rings and aggregation of fluoroalkyl chains. Among the various substituted styrene dimers on the benzene rings, 4-hydroxylated styrene dimers (2) were found to exhibit unique properties on the basis of their self-assembly. The OH groups on the benzene rings may work effectively for the self-assembly of the dimers in addition to the π,π-stacking of the benzene rings and aggregation of the fluoroalkyl chains. Especially rac-2 worked as the host molecule for inclusion of alcohols on recrystallization from hexane with a small amount of alcohol. The synthesized styrene dimers are expected to have high potential as novel fluorinated functional materials.