Study On Near Infrafred Fluorescent Dyes Based On Benzothiadiazole In Assembly

Near infrared fluorescent dyes are a new type of dyes developed in recent years.As an important organic fluorescent material,benzothiadiazole fluorescent materials have attracted much attention because the fluorescence emission wavelength can reach the near infrared region.Near infrared fluorescence imaging technology can be applied to biological imaging because of the obvious advantages,such as achieving deeper tissue penetration and reducing background self fluorescence interference from organisms and tissues.We explored through several routes,synthesized NIR-① with benzothiadiazole as the main body,and the emission wavelength was about 980 nm.On the basis of NIR-①,we also synthesized NIR-②with longer emission wavelength by introducing thiophene group,and the emission wavelength was about 1100 nm.Then,we explored the interaction between dyes and supramolecular macrocyclic host.In order to improve their fluorescence properties in water,amphiphilic assemblies were constructed by using the host guest inclusion ability of sulfonated calixarene.This assembly has a series of advantages such as fast,simple and easy to prepare.Due to the luminescent phenomenon of fluorescent dyes,the assembly also has strong fluorescence emission ability.At the same time,the assembly has good stability.The selected surfactants are sulfonated calixarene SC4AD、SC6AD、SC8AD,cyclodextrinα-CD、β-CD、γ-CD and POPC.After many experiments,we found that SC4AD could complexed with NIR-①,SC6AD could complexed with NIR-②,so that the fluorescence intensity in aqueous solution was improved.And with the change of time,the complex had good stability compared with other surfactants.This provides a new way to solve the problem of poor fluorescence performance of benzothiadiazole fluorescent dyes in water.