Pyrene-labeled deoxyuridine and deoxyadenosine: fluorescent discriminating phenomena in their oligonucleotides

Pyrene-labeled deoxyuridine (UP) and deoxyadenosine (AP) units, which are substituted at the C-5 and C-8 positions, respectively, are fluorescent unnatural nucleosides. When duplexes are formed, these nucleobases feature strong and stable interstrand stacking interactions between the two pyrene units, which compensate for the loss of hydrogen bonding and induce characteristic pyrene excimer emissions.