Photostabilities of novel heptamethine 3H-indolenine cyanine dyes with different N-substituents

Novel near-infrared (NIR) 3H-indocyanine dyes with different N-substituents were synthesized and tested to make clear the relationship between photophysical properties and structures and develop potential NIR cyanine dyes with high photostability for fluorescent imaging technology. The electron-withdrawing ability of the substituents on N-position of 3H-indolenine strongly affects the photostabilities of the NIR cyanine dyes and introducing of the electron-donating groups is favorable to obtain NIR cyanine dyes with improved photochemical stability.