Design, Synthesis And Application Of Fluorescent Sensing Materials Based On Naphthalimide

Naphthalimide derivatives have many advantages, such as high fluorescence quantum yield, photostability, chemical stability and large Stokes shift, so they have been widely used in designing and developing fluorescent sensors and organic optoelectronic materials. In this paper, we have designed and synthesized three kinds of fluorescent sensing materials based on naphthalimide derivatives. All the target compounds obtained were characterized by 1H-NMR, 13C-NMR and HRMS. The fluorescent sensing material PNME and separating material SM were characterized by TEM image.1. A polymeric fluorescent sensor PNME which exhibited dual responses to pH and temperature was designed and synthesized. The pKa value of PNME was 7.20, and its diameter was 50 nm. These data demonstrated that PNME could be endocytosed and accumulated in lysosomes. PNME could be used as an intracellular pH sensor for lysosomes imaging in living cells. Moreover, it could be used as a thermometer to detect the temperature range from 32 to 40℃in neutral aqueous solution. It also can sense intracellular temperature change through a variation in its fluorescence.2. NPAP, a naphthalimide-based turn-on fluorescent sensor for Fe3+ ion was designed and synthesized. NPAP revealed a high selectivity to Fe3+ ion in solution. After silylation, NPAP was covalently bonded to the silical particles to be a turn-on fluorescent sensing material FS. FS showed a good linearity (correlation coefficient R2=0.9023) in the range of 20-140μM of Fe3+ ion.3. SM was designed and synthesized to separate lithium from brine, by using 14-crown-4 crown ether as lithium ion receptor. The maximum adsorption capacity of SM was 3.1 mg g-1. Moreover, we have also synthesized compound D7, with 14-crown-4 crown ether as an lithium ion receptor and naphthalimide derivative as fluorophore. The UV absorption and fluorescence of D7 did not change after addition of lithium ions, but the MS spectrum showed that D7 can combine with Li+...