Synthesis and properties of fluorene-oligothiophenes perylenediimide triads and their electropolymerizations

A series of novel donor-acceptor-donor triads, namely PFTn (n = 0-4), consisting of fluorene-oligothiophenes (FTn) as a donor and perylenediimide (PDI) as an acceptor were synthesized and characterized. The chemically bonded electron donor and acceptor chromophores in the triads were found to be independent. These triads showed a strong intramolecular photo-induced electron transfer (PET) between both chromophores, which gave rise to a quasi-quantitative fluorescence quenching of both PDI and FTn moieties. Distinctively, a reverse energy transfer from the acceptor PDI to the donor FTn induced a strong fluorescence emission from the FTn moieties in the triads PFT3 and PFT4. The PFTn (n = 1-3) triads were proven to undergo an electrochemical oxidative coupling reaction and become electropolymerizable materials to form polymer plastic films (poly(PFTn)), while PFT4 proved to be an electrochemically stable molecule.