Syntheses And Research On Application Of Squarylium And Hemicyanine Dyes Based On 2,3,3-Trimethyl-3H-Indolium

Cyanine dyes possess many good characteristics such as high extinction coefficient, simple routs of syntheses and steps of purification, proper fluorescence quantum yield, etc. These make them be used as organic solar cells, pH probes and ion sensors, and so on. Cyanine dyes can also be applied in biological yields since they can associate with many bio-molecules such as protein or nucleic acid with changes of spectra in wavelength and intensity. In this thesis, cyanine dyes based on 2,3,3,-trimethyl-3H-indolium are synthesized and their corresponding properties are studied.Three squarylium dyes have been designed and synthesized for improving their limited photo-stability and low water-solubility. The results show the introduction of carbamoylmethyl group can improve photostability of the dyes, decrease the aggregates and increase molar extinction coefficient and fluorescence quantum yield in water. The results of the dyes association with BSA present a better linear relationship between the fluorescence intensity of the dyeⅡb and BSA concentration can be obtained, which indicate the dye can detect BSA quantitatively in the range of 0.02-3μmol/L.Six bis-hemicyanine dyes with different linking groups based on styrene cyanine dyes have been synthesized in order to decrease the self-fluorescence of the dye in water and increase the sensitivity in association with biomolecules. The results show the fluorescence intensity of dye IIIc enhance 90 times after association with DNA, and the number is 15 times of that of corresponding mono-cyanine dyeⅢa. On the other hand, after interaction with BSA, the fluorescence intensity of the dyeⅢh increase about 19 times, which is 13 times of corresponding mono-cyanine dyeⅢe. Moreover, four bis(hemicyanine) dyes are membrane-permeable in live cells, which indicate they have potential to visualize the organelle in live cells.A series of styrene cyanine dyes with solid-state emission have been developed. The X-ray diffraction data show there are no obvious n-πstacking interaction between adjacent dye molecules, which lead to their intensive emission in solid-state. The anion of the dye plays an important role in the formation of the crystals because it can form H-bond with atom H in different position of the dye.Five pH probes based on styrene cyanine dyes have been synthesized. Their properties as pH probe are tested in water-ethanol mixed solvents. The results show their spectra change obviously with the shift of the wavelength when the pH of the solution is changed. The data indicate the pKa of four probes is fit to sense the acid organelle in live cells. The four probes are membrane-permeable in live cells and can be used to fluorescence image in live cells. Moreover, probe Vd behave dual-emission and can dual-color fluorescence image in live cells.