Phenanthridinium as an Artificial Base and Charge Donor in DNA

摘要

3,8-Diamino-5-ethyl-6-phenylphenanthridinium, known as "ethidium", has been widely used in fluorescence assays with nucleic acids. Ethidium and its derivatives are also potent trypanocidal drugs. In addition, ethidium represents an important donor for photoinduced charge transfer processes in DNA.[3–6] Relative redox potentials indicate that ethidium in the photoexcited state (Et~(*+)) is not able to oxidize or reduce DNA to initiate hole or electron hopping, respectively. Hence, a suitable charge acceptor has to be provided. 7-Deazaguanine quenches the emission of ethidium in DNA and has been applied as the acceptor in holetransfer studies.