A Sequential Electron-Transfer Relay in Diperphy rin- Porphyrin- PyromcHitimide Triads Analogous to That in the Photosynthetic Reaction Center

摘要

The reaction center (RC) of photosyntheuc bacteria contains a number of cofactors that mediate a series of fast electron transfers, yielding an oxidized electron donor and a reduced election acceptor on the opposite sides of a membrane. The key stepsin. this process are the initial charge separation (CS) between tetrapyrrolie pigments and the subsequent charge-shift reaction (CSH ) to a quinone acceptor to generate a stable, longlived, charge-separated state. Numerous model compounds have been prepared to understand the (actors controlling electron transfer (E:T) reactions in these highly complex systems. In the past decade the advantages of multiple electron transfers have been amply demonstrated. Nevertheless, modeling the sequential electron transfer relay of the reaction center remains very difficult, particularly with regard to the ET reaction scheme outlined above.