双羟基七甲川菁染料的合成及其光谱性能研究

Synthesis and spectral properties of dihydroxy heptamethine cyanine dyes

通过分子设计,分别以2,3,3-三甲基吲哚和1,1,2-三甲基-1H-苯并[e]吲哚为原料,首先合成两种季铵盐,再分别同2-氯-1-甲酰-3-羟基亚甲基环己烯缩合,利用Suzuki-Miyaura反应实现染料中位C-C偶联,以超过70%的收率制备了4种带有活性羟基的七甲川菁染料。利用核磁和高分辨率质谱对染料结构进行了表征。以乙醇为溶剂,用紫外-可见光谱仪考察了染料的光谱性能。采用电流为13.4 A的高压氙灯为光源,考察了染料的光稳定性。探究了pH对染料颜色的影响,并尝试推论变色机理。结果表明,4种七甲川菁染料均在近红外区产生较强吸收,在无水乙醇中均具有良好的光稳定性。不同pH下,染料的光谱性能研究发现,七甲川菁染料吸收光谱受pH影响较大,在pH=5~7时,染料在近红外区有最佳吸收。

Four heptamethine cyanine dyes with active hydroxyl groups were prepared by molecular design using 2,3,3-trimethylindole and 1,1,2-trimethyl-1 H-benzo[e]indole as raw materials and their yields were over 70%.First,two kinds of quaternary ammonium salts were synthesized and then condensed with 2-chloro-1-formyl-3-hydroxymethylene cyclohexene,respectively.Finally,median C-C coupling of dyes was carried out by Suzuki-Miyaura coupling reaction.The structures of dyes were characterized by 1 HNMR and FTMS spectra.The absorption spectra of four dyes were determined by UV-Vis spectrometer with ethanol as solvent.The light stability of dyes was investigated by using a high voltage xenon lamp with a current of 13.4 A as the source of the light.The effect of pH on the color of dye was studied,and the mechanism of color change was deduced.The results showed that four heptamethine cyanine dyes had strong absorption peaks in the near infrared region and exhibited good light stability in anhydrous ethanol.Their absorption spectra were greatly affected by pH value.These dyes had the best absorption in the near infrared region when pH value was in the range from 5 to 7.