Photoinduced electron transfer reaction in diaminostilbene-tethered DNA duplexes.

DNA duplexes containing diaminostilbene (DAS) as a photoinduced electron donor were synthesized to investigate mechanisms of electron injection into DNA and the succeeding electron transfer in the duplexes. DAS-Capped hairpin DNA showed a high structural stability thereby attains large interaction between DAS and the terminal base pair. DAS-Tethered DNA by a single linker at the end of the duplex was also synthesized and the yields of photoinduced electron transfer through mismatched base pairs were quantified. Both duplexes showed similar electron transfer efficiencies depending on the base pairs, which suggests DAS stacks well on the "pi-way" of the duplex DNA.