Studies On Synthesis And Properties Of Benzindocyanine Dyes

Benzindocyanine dyes have become one of the most important organic functional dyes. They are widely used in optical disc, biological analysis and organic solar cell etc because of their unusual structures and functions. Besides a concise review on the structure, synthesis and new applications of benzindocyanine dyes, this thesis deals with studies on synthesis and properties of benzindocyanine and benzindohemicyanine dyes.Eight kinds of novel symmetric benzindolium heptamethine cyanine dyes containing chloro-substituent in polymethine chain have been synthesized and characterized by ~1H NMR, MS, IR and UV-vis. The UV-vis spectra of these dyes in different solvents, temperatures and illumination time have also been measured. The results indicate that with the increasing of refractive index of solvent, the maximum absorption wavelength of these dyes has a red-shift;all the dyes have good thermostability at 25~65 ℃ and the photooxidation reactions of them follows first-order kinetics in methanol. Meanwhile, we study the aggregation of 3,3,3',3'-tetramethyl-1,1'-dipropyl-10-chloro-4,5-benzindolium heptamethine cyanine hexfluorin phosphate (2c) in solution and the thermodynamic properties of 3,3,3',3'-tetramethyl-1,1'-dibutyl-10-chloro-4,5-benzindolium heptamethine cyanine hexfluorin phosphate (2d). It is found that the aggregation of dye 2c is effected by solvents and salts, and dye 2d exists the dimerization equilibrium in 50 % aqueous methanol solution, and the enthalpy of dimerization of dye 2d is -24.79 kJ/mol at 23.0~43.5 ℃.With the assistance of microwave irradiation, two series of novel dyes have been synthesized under solvent-free condition. All of the compounds have been characterized by ~1H NMR, IR, UV-vis and elemental analysis. The UV-vis and fluorescence properties of them are also investigated.