Study On Structures And Properties Of Aminocyanine Dyes

Fluorescent dyes, due to its high sensitivity, easy operation, are widely used in fluorescence immunoassay, fluorescence probe, cell dyeing, etc. Near-infrared (NIR) fluorescent dyes’absorption wavelength, which lies in the NIR region (from700nm to900nm), can minimize photo damage and avoid the influence of cell autofluorescence. Thus, Near-infrared (NIR) fluorescent dyes are becoming more and more important in modern imaging techniques of biomedicine. Our group had synthesized two heptamethine cyanine dyes by introducing alkylamino groups at the central position in2005. They have a large Stokes shift (>140nm) and strong fluorescence which make them more suitable for use as fluorescence probes than common cyanine dyes.In this paper, we designed and synthesized two novel dyes by using cyanine dyes as matrix and named them as CyH1and CyH2. The structure of CyHl was determined by the single crystal diffraction. CyH1and CyH2showed a large bathochromic shift (>130nm) in dichloromethane and water respectively. CyHl and CyH2were sensitive to acid. After adding with H+, the color of CyH1and CyH2changed from yellow to red, and can be seen with "naked" eyes. Furthermore, CyH1had good localization in mitochondria which can be used as a tracker with double absorbance and emission.Meanwhile, the structure of amincyanine dyes were studied. We synthesized four dyes, CyNl, CyNIA, Cy7-3and Cy7-1. The absorption spectrum of Cy7-1appeared an absorption peak at226nm and the absorption peak was determined as iodide ions. However, iodide ion was not found in CyN1. Therefore, we considered CyN1should be a neutral structure. The infrared spectrum of CyNl had shown that there was no N-H (secondary amine) bond. Those two evidences proved that there was no iodide ions in CyN1.