Synthesis And Spectral Properties Of New Water-soluble Indole Trimethine Cyanine Dyes

Using indole derivative with sulfonic acid group as starting material, different quaternary ammonium salts were synthesized by reacting with N-alkyl reagents. Finally, the six watersoluble chainlike indole trimethine cyanine dyes were obtained. The experiment specific work include the following detail.The syntheses of unilateral substituted and symmetrically cyanine dyes are as follow: 2,3,3-trimethyl-3H-indole-5-sulfonic acid was synthesized by reaction of phenyl hydrazine sulfonic acid with 3-methyl-2-butanone, and the potassium salt was obtained by reacting with potassium hydroxide. And than two kind of main intermediates of 1-(4-cyanidebenzyl)-2,3,3- trimethyl-3H-indole-5-sulfonates and 1-(4-methylbenzyl)-2,3,3-trimethyl-3H-indole-5- sulfonates were obtained from the different of N-alkyl reagents. At last, four novel dyes were synthesized by condensation of the intermediates and triethyl orthoformate. The dyes were purified by C-18 reverse phase column chromatograph. The structures were confirmed by 1H NMR, IR and MS, all data means that synthesized compounds are target products.The syntheses of asymmetric cyanine dyes are as follow: Two novel dyes were synthesized by different quaternary ammonium salts and triethyl orthoformate. The structures were confirmed by 1H NMR, IR and MS, all data means that synthesized compounds are target products.The tests of spectral properties are as follow: Spectral properties of dyes in different kinds of solvents were studied. The relationship between molecular structures and spectral properties were investigated. The results show that maximum absorption and maximum emission wavelength of six novel dyes are in the range from 445 to 589 nm. Spectral properties of dyes in aqueous solution of different pH were investigated. The results show that unilateral substituted cyanine dyes can be used as pH probe. Spectral properties of dyes in aqueous solution of CTAB, SDS and TX-100 were investigated. The results show that the maximum absorption and emission spectral of the dyes changed with the change of concentrations in aqueous solution of surfactants. All these provide a reference for biological applications of dyes.