Several Types Of Cyanine Dyes: Preparation And Optical Properties

In the preparation and application of functional dyes, due to its excellent optical performance, their linear optical properties and nonlinear optical properties have been extensively studied. In linear optics, absorption and fluorescence emission properties of functional dyes were studied, which can be applied to biological probes, biological tissue staining as well as in areas such as medical diagnostics. In nonlinear optics, second-order nonlinear optical properties and third-order nonlinear optical properties of functional dyes were studied, which can be applied to nonlinear optical materials, optical limiting, optical switches and other fields. Cyanine dye was one of the most important functional dyes, due to their unique conjugated skeleton structure, designability, adjustable absorption and emission wavelengths and excellent optical properties of cyanine dyes, they are widely used in the nonlinear optical materials, biological probes, biological tissue staining and other fields. The design and synthesis of new cyanine is becoming one of the important foundation of organic photovoltaic materials research. Because of simple operation, high sensitivity, relatively little damage to cells and organisms, fluorescent biological probes were widely used in biological analysis field. The hydronium ion is one of the most important chargedspecies that plays an extremely important role in biological processes occurring in live cells and tissues such as proliferationand apoptosis, multidrug resistance, ion transport, endocytosisand muscle contraction, developing new p H probes is urgently needed. The understanding of DNA/RNA organization and structure in vivo is so important, fluorescent staining techniques using organic DNA/RNA-binding molecules are required for biological research and medical diagnosis, including cellular imaging and DNA/RNA quantification. Nonlinear optical material is an important basis of photonic technology, in which the third-order nonlinear optical materials are widely used in various high-tech applications.This paper introduces several types of preparation and optical properties of the cyanine dyes, which is divided into four parts, the first three parts mainly introduce linear optical properties of the cyanine dyes and their application in biological detection, the fourth part mainly introduces the nonlinear optical properties of the cyanine dyes and their application in the third-order nonlinear optical materials. Details as follows:1.Two indolium-phenol based tetramethylene hemicyanines(5a-5b) were designed and synthesized. Probe 5a has colorimetric response at 455 and 578 nm by the protonating and deprotonating processes, its emission spectra shows ratiometric changes at 594 and 654 nm with large Stokes shifts under acidic condition(139 nm) and basic condition(76 nm). The bromide substituent of the hemicyanine(5b) has lower p Ka value compared with unsubstituted hemicyanine(5a), which suggests that adjustable p Ka can be achieved by the modification of electron withdrawing groups. Moreover, the in cellulo fluorescence imaging shows that the probe 5a can be used in the detection of intracellular p H levels.2. A series of hemicyanines(7a-7f) with terminal amino groups were designed and synthesized. They all exhibited fluorescence from 600 to 850 nm with emission maxima in the near-infrared region. The hemicyanine dye with the benzothiazolium group(7d) exhibited the best photostability and thermal stability among those tested. The potential application of 7d as a nucleic acid-staining fluorophore was evaluated. Fluorescent responses were observed from 575 to 850 nm when 7d was titrated with commercially available DNA and RNA. Dye 7d was used in the selective fluorescent staining of RNA in live He La, KB and V79 cells. The results indicated that 7d can be used as a near-infrared fluorescent probe for nucleolus imaging in live cells.3.Two positively charged substituent chain containing hemicyanine dyes(8a-8b) were designed and synthesized, and their maximum emission peaks are in the near-infrared region. Comparing to probe 7d, when probe was titrated with commercially available DNA and RNA, the fluorescence intensity of 8a respectively increase 16.4 times and 13.2 times, the fluorescence intensity of 8b respectively increase 31.5 times and 24.7 times. Moreover, the probe 8a can be used as a near-infrared fluorescent probe for nuclei imaging in fixed He La cells, the probe 8b can be used as a near-infrared fluorescent probe for nucleoli and cytoplasm imaging in fixed He La cells. In addition, the probe 8a and 8b can be used to distinguish between live and dead cells.4.Two Symmetrical trimethine cyanine(11a-11b) with quinolone groups were designed and synthesized. The trimethine cyanine with quinolone skeleton(11a) shows strong reverse saturable absorption and nonlinear refraction in dimethyl formamide solution at 532 nm. Then, its derivative compound(11b) with long alkyl chains was synthesized in order to improve the film forming performance, the spinning coating thin film exhibits strong reverse saturable absorption with the third-order nonlinear susceptibilities χI(3) = 3.42×10-8 esu and χ(3) = 3.23×10-9 esu under nanosecond and picosecond laser beams respectively.