Chloride-promoted self-assembly and photoluminescence of naphthalene diimides tethered to polyacetylene

Abstract

With the aim of developing a system with tunable self-assembly of π-conjugated building blocks, an optically active helical polyacetylene bearing amide groups and naphthalene diimide (NDI) derivatives in the side chains is reported. The helical conformation of the polymer backbone and the stacking pattern of the pendant NDIs can be regulated by adding trifluoroacetic acid or specific solvents or anions. In particular, Cl⁻ can induce a dynamic reorganization in molecular arrangement of naphthalenediimides from H-type to J-type aggregates along with turning fluorescence emission on at 515 nm. Consequently, the self-assembly of NDIs is effectively controlled, which can lead to the regulation of the properties of NDI-based materials. To the best of our knowledge, this is the first time that the optically active helical polyacetylene has been applied in the regulation of stacking modes of NDIs. This strategy has shown great potential for anion recognition and the design of stimulus-responsive materials.