Synthesis Of Indocyanine Dyes And Their Co-crystals

Indocyanine dyes are cyanine dyes and have many excellent characteristics,such as large molar extinction coefficient,high fluorescence intensity after combining with biological macromolecules,large controllable range,simple synthesis,good spectral characteristics,and high fluorescence quantum efficiency,the maximum absorption wavelength can reach the near-infrared region,etc.At present,it has been widely used in the fields of near-infrared biological fluorescent dyes,photographic technology,and fluorescent labeling of biological macromolecules.The designed synthetic route uses different substituted aromatic hydrazine as raw materials,and 3-methyl-2-butanone is used for Fisher synthesis to obtain cyclization products,and then different N-alkylated reagents are used to quaternize the N atom to form N-alkylated product is then used as an electrophilic reagent to attack the nucleophilic methyl group on the2 nd position of the indole heterocyclic quaternary ammonium salt.Finally,the N-alkylated product is subjected to a condensation reaction to obtain asymmetric indole cyanine class target product.The synthesis process in the condensation stage of asymmetric indole cyanine compounds was studied,and it was found that the optimal reaction conditions were that the molar ratio of ethyl intermediate 2,caproic acid intermediate 3 and condensation reagent S was 1:1:1,and the reaction temperature is 100°C,the reaction time is 30 minutes,and the yield is significantly improved.The optical properties of a series of asymmetric indocyanine dyes were studied,and the influence of the length of the linear conjugated methane chain and the introduction of water-soluble groups on the benzene ring on the absorption intensity of the dye was analyzed which provided a theoretical basis for the controllability of intensity of the absorption of indocyanine dyes.It is found that for every additional unit of the conjugated methyl chain unit,the maximum absorption wavelength increases by 100 nm,and the introduction of water-soluble sulfonic acid groups on the benzene ring causes the maximum absorption wavelength to slightly red shift.From the perspective of eutectic materials,a series of indole cyanine eutectic materials have been prepared.A kind of pyrene indole hemicyanine dyes with an intramolecular push-pull electronic structure were designed and prepared as donor molecules,TCNB and TCQ was used as acceptor molecules.This kind of eutectic material was analyzed by a series of testing methods,and the problems of molecular orientation,intermolecular interaction,molecular stacking mode were also explored,and the solid macroscopic optical properties were studied.It is found that the eutectic phase has advantages in stability and optical properties compared to the monomer.