Novel chemical cyclization routes to prepare ladder-type conjugated molecules

Novel chemical cyclization methods using BBr3 and fluoride have been successfully developed to produce ladder-type conjugated molecules. Both electron rich and electron poor conjugated polymers were readily prepared by BBr3-promoted cyclization method both in solution and on film. Extension of the π-conjugated systems caused by their rigid planar structures was confirmed by the absorption or emission spectroscopy. A fluoride-induced aromatic cyclization method was also developed and an application to fluoride ion sensing scheme was suggested.