| Cyanine dyes, which are characterized by large molar extinction coefficient, high fluorescence quantum yeilds, relatively high stability, low melting points, large tunable range of maximum absorption wavelength and easy preparation, act as one of the most important organic functional dyes in many processes of technological field, such as sensitizers in photography, infrared laser dyes, optical disc recording media, sensitizers in solar cell, nonlinear optical materials and so on. In recent years, many cyanine dyes are used in biomedical field, such as DNA detection, gel staining, DNA sequencing, protein analysis, photodynamic therapy (PDT), cell imaging, anticancer agent and so on. Monomethine cyanine dyes and styryl hemicyanine dyes are two kinds of the most important organic functional dyes, and they have great application prospect.In this paper the structure features, classification, properties and application of cyanine dyes, and the preparation of monomethine cyanine dyes and styryl hemicyanine dyes in recent years are introduced.The main content of this research are as follows:1. Three novel kinds of water-soluble styryl hemicyanine dyes were prepared. The products were identified by1H NMR, IR, UV-Vis spectroscopy. In the synthetic process, it could be found that the sequence of the reaction activity of benzaldehyde was p-dimethylaminobenzaldehyde>p-methoxybenzaldehyde>p-hydroxybenzalde- -hyde. The?max and s of the dyes were 563.0nm,550.Onm,539.Onm and 6.17×104,0.09×104,0.72×104 L-mol-1·cm-1, respectively. At room temperature, the fluorescence maximum of D1 was located at 591.6nm and its fluorescence quantum yield was 0.0011 in Trist-HCl buffer. The absorption properties of prepared dye D1 in the presence of DNA/BSA were investigated. The dye had an affinity for BSA, but not interacted with DNA.2. Eight monomethine cyanine dyes were synthesized by a new one-pot method. The products were identified by1H NMR, IR, UV-Vis and HRMS, spectroscopy. Compared with the traditional methods, the new synthetic method reduces the reaction steps, shortens the reaction time, avoids the separation and purification of the intermediate and reduces costs. In the synthetic process, it could be found that the reaction activity of heterocyclic iodized salts was higher than heterocyclic propane sulfonic salts. The dyes absorbed in the region 495.0?560.0 nm and had molar extinction coefficients of 1.3×104?9.4×104L·mol-1cm-1. Their fluorescence maxima, fluorescence quantum yields and Stokes shifts were in the range of 531.0?594.0 nm,0.00010?0.00064 and 16.0-80.0 nm in different solvents, respectively. The?max had relationship with the properties of the solvents. The?max of dyes were shorter in protic solvents. Moreover, the?max shows blue-shifted with the increasing polarity of the solvents.3. Eight monomethine cyanine dyes were synthesized and the products were identified by1H NMR, IR, UV-Vis and HRMS spectroscopy. In the synthetic process, it could be found that the reaction activity of 1-methyl-2- methylthiobenzo[c,d]indolium was higher than 2-methylthiobenzo[c,d]indolium iodide. The dyes absorbed in the region of 495.0-614.0nm and had large molar extinction coefficients (near to 104 L-mol-1cm-1). Their fluorescence maxima, fluorescence quantum yields and Stokes shifts were in the range of 583.0-636.0nm, 0.00043?0.017 and 25.0-80.0 nm in different solvents, respectively. The fluorescence quantum yields of dyes in protic solvents were higher than that in nonprotic solvents. Moreover, in the D-?-A structure of dyes, the synergistic effect of benzo[c,d]indole and benzothiazole was much better than that of benzo[c,d]indole and quinoline, and improved the rigid of the dyes.4. The crystal structure,1H NMR, IR and UV-Vis were studied by theoretical method(DFT/TD-DFT). The results showed that all of the calculated spectrum data were in agreement with the experimental data. From the molecular orbitals, the absorption in dyes was the first dipole-allowed???* transition from HOMO to LUMO. |
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