Energetics and rate of electron transfer in DNA from base radical anions to electron-affinic intercalators in aqueous solution

The dependency of the rate of intramolecular electron transfer in DNA in aqueous solution on the free energy change (ΔG°) and distance (L) is determined by observing electron transfer from DNA base radical anions to a series of eight compounds which are randomly intercalated into the DNA. Electron transfer initiated in DNA is found to be activation energy-controlled with k=k° exp(constant/L), which is different from published studies on electron transfer between photodonor–acceptor complexes attached to DNA that invoke an electron tunnelling description.