A new turn-on fluorescent chemosensor based on diketopyrrolopyrrole (DPP) for imaging Zn super(2+) in living cells

A new turn-on fluorescent chemosensor, DPPL sub(1), was rationally designed and synthesized based on diketopyrrolopyrrole (DPP), which presented high sensitivity and selectivity for Zn super(2+). Specifically, DPPL sub(1) presented a large emission enhancement and a 70 nm blue-shift upon Zn super(2+) binding. super(1)H NMR titrations, studies into the pH effects and DFT calculations further proved that this phenomenon was due to both photo-induced electron transfer (PET) and intra-molecular charge transfer (ICT) processes. More importantly, DPPL sub(1) was successfully used for imaging Zn super(2+) in living HeLa cells. To the best of our knowledge, this is the first DPP-based fluorescent chemosensor to recognize Zn super(2+) ions in living cells with a large blue-shift and a fluorescent enhancement based on both photo-induced electron-transfer (PET) and intramolecular charge-transfer (ICT) effects. Meanwhile, we have also provided a new effective platform for the development of fluorescent chemosensors for other analytes.