Pendant-Type Helicene Oligomers with p-Phenylene Ethynylene Main Chains: Synthesis, Reversible Formation of Ladderlike Bimolecular Aggregates, and Control of Intramolecular and Intermolecular Aggregation

摘要

Pendant-type (P)-helicene oligomers with p-phenylene ethynylene main chains up to a tetrarner were synthesized by a building block method, The (P)-tetrarrier reversibly formed a ladderlike bimolecular aggregate upon cooling and disaggregated upon heating in (trifluorometlhyl)benene. Two bis(tetramer)s in which two (P)-tetramers were connected by hexadecthnethylene linkers, were: also synthesized. The head-to-tail bis(tetramer) formed an intrainoleenlar aggregate, and the head-to-head bis(tetramer) formed an intermolecular aggregate in toluene. The results suggest the antiparallel aggregation structure of the pendant-type (P)-tetramers. The structure of the linker was proved to be effective in Controlling intramolecular and intermolecular aggregations.