Triazolylpyrenes:: Synthesis, fluorescence properties, and incorporation into DNA

Synthesis of 1,6- and 1,8-triazolylpyrenes and their incorporation into oligonucleotides is described. In hybrids, triazolylpyrenes adopt interstrand stacking interactions. Exciton coupling is observed for the duplex containing a pair of the 1,6-isomer indicating a well-defined helical arrangement of the triazolylpyrene building blocks. Triazole substitution results in pronounced red-shifts of monomer as well as excimer fluorescence. Furthermore, quantum yields of the formed excimers are remarkably high.