Highly soluble perylene tetracarboxylic diimides and tetrathiafulvalene–perylene tetracarboxylic diimide–tetrathiafulvalene triads

Two donor-σ-acceptor-σ-donor triads incorporating tetrathiafulvalene (TTF) and 3,4,9,10-perylene tetracarboxylic diimides (PDI) units were synthesized. The structures of the triads and their intermediates were characterized by 1H NMR, 13C NMR, MS, IR. The results of UV–vis and cyclic voltammetry (CV) of the triads indicated negligible intramolecular charge transfer (ICT) interaction in their ground states. The fluorescence and fluorescence lifetimes of the triads were reduced compared to PDIs, which evidently indicated that photoinduced electron transfer (PET) interaction occurred from the TTF unit to the PDI unit in the excited state. The fluorescence intensity of the triads could be reversibly modulated by sequential oxidation and reduction of the TTF unit using the chemical methods. Therefore two new fluorescence molecular switches based on TTF and PDI units were established.