Self-assembly of cyclobis(paraquat-p-phenylene)s

摘要

Cyclobis(paraquat-p-phenylene)s complexed with anionic surfactants exhibit liquid-crystalline states and form pseudo-rotaxanes with tetrathiafulvalene in the condensed states.rnMolecular assemblies such as polymers, gels and liquid crystals have great potentials as functional soft materials. Among them, liquid crystals are complex fluids forming self-organized anisotropic structures. In the design of functional liquid-crystalline (LC) structures, introduction of functional molecular moieties in the LC nanostructures is one of promising approaches. Our intention here is to induce LC properties for ionic cyclic moieties. Cyclobis(paraquat-p-phenylene) is one of the fundamental components for supra-molecular chemistry such as rotaxanes and catenanes. The cyclophane, which has a rigid structure and an electron-deficient cavity at its centre, forms a variety of charge-transfer complexes with π-electron-rich molecules such as hydroquinone, tetrathiafulvalene (TTF), and oligothiophenes. If cyclo-bis(paraquat-p-phenylene) derivatives form LC structures, guest recognition in self-organized states could be achieved. Our design here is to form complexes of the cyclophane with surfactant molecules. Complexation of ionic molecules with oppositely charged surfactants such as alkyl sulfate, dialkyl sulfosuccinate and dialkyl phosphate were reported to lead to the formation of LC structures via electrostatic interactions.