Synthesis、spectra And Application Of Indol-cyanine Probes And Phenanthroimidazole Fluoride Anion Probe

As a typical near-infrared (NIR) fluorescent probe, cyanine probes have attractedimmense interest in the fields of ion detection、bioanalysis and angiography. Herein, aheptamethine indol-cyanine compound4was synthesized. Then four probes wereachieved by nucleophilic reaction at the chlorine of the compound4.Their photochemical properties were investigated. It was found that differentsubstitutions (piperazine, morpholine) at the central position of the compound led todiverse optical properties. Besides, the modification of the heterocycles at the middleposition had great influence on the spectroscopic properties. It was also found thatwith the alkaline of the hetero atom increasing, the maximum absorption wavelengthwould move to the long-wave direction, and the fluorescence quantum yield wouldreduce.All of the four probes had large Stokes shift, and their absorption spectra andemission spectra of these probes were wider than those of compound4, and both twospectra didn’t have mirror symmetry relations. It was indicated that the phenomena ofintramolecular charge transfer (ICT) was existed in such derivatives.We investigated the optical properties of probe5-8toward the change of pHvalue. It was found that the absorption spectra of probe5and6changed obviously,but emission spectra changed little. Probe7and8were more sensitive, under acidicconditions, they showed obvious changes in both absorption and emission spectra.A compound10whose Stokes shift was183nm was synthesized based on thephenanthroimidazole-cyanine platform. It can be used as a NIR probe because itsemission spectra were in NIR region. The compound10had been indicated to be afluoride anion probe with good sensitivity and high selectivity. What’s more, thedetection of fluoride anion by probe10could be observed by naked-eye.