Synthesis And Application Studies Of Near-infrared Fluorescent Sensors For Sulfide Detection

Sulfide anion(S^2-) has been known as toxic species for many years. Notably, hydrogen sulfide?H2S?, as its protonated product, is recently recognized as the third endogenous gaseous transmitter and is related to many diseases. Herein, we report two fluorescent sensors for S^2-detection which are constructed with hydroxyl Nile-red or hydroxyl porphyrin.Hydroxyl Nile-red has high fluorescence quantum yield, photo and p H stability. It is easy to be synthesized because of small molecule. The probe1 displays weak fluorescence due to the photo-induced electron transfer?PET? process which occurs from Nile-red fluorophore to the electron-withdrawing2,4-dinitrobenzenesulfonyl group. When the 2,4-dinitrobenzenesulfonyl moiety is removed by nucleophilic substitution with the hydrosulfide anion, probe 1 is converted into hydroxyl Nile red, eliciting a S^2-induced fluorescence turn-on signal. Furthermore, probe 1 has high selectivity and sensitivity for the sulfide anion. It can be applied to detect S^2- in tap water.Since it is relatively less toxic, its potential for biological applications was confirmed by using it for real-time fluorescence imaging of hydrogen sulfide in live nerve cells.As porphyrin has a good property of tissue penetration and is a natural fluoropho res, according to the mechanism of electron transfer photoinduced, a new near-infrare d fluorescence probe containing NBD-modified tailed porphyrin which can be used in sulfide anion detection is prepared in this paper. Compared with the conventional small molecule organic fluorescent probes, e fluorescent probe with a longer emission wavelength??em> 650nm?.Upon being with S^2-, the significant NIR fluorescence enhancement can be observed. The sensor shows high sensitivity, high selectivity and can be used for real-time detection for S^2-.