Ultra pseudo-Stokes shift near infrared dyes based on energy transfer

Novel fluorescent dyes with ultra pseudo-Stokes shift were prepared based on intramolecular energy transfer between a fluorescent donor and a cyanine-7 acceptor. The prepared dyes could be excited at ∼310 nm and emit fluorescence at ∼780 nm. The energy transfer efficiencies of the system are found to be >94%.