Electron-transfer reactions in organic chemistry

The Intersecting-State Model (ISM) is used to calculated the absolute rate constants of self-exchange electron-transfer reactions (ET) of organic species. The systems studied include aromatic hydrocarbons, quinones, nitrobenzene, aromatic nitriles, tetracyanoethylene, aromatic amines, and alkylhydrazines. All of the calculated rates are within one order of magnitude of the experimental ones, and the correlation coefficient between the two sets is 0.96. An electron-tunneling model has been developed to calculate distance-dependent nonadiabatic factors of intramolecular ET. This model can be used with ISM to calculate intramolecular ET rates. The system biphenylyl-spacer-naphthyl in tetrahydrofuran, whose distance-dependent intramolecular rates were measured by Closs and Miller, was used to test our calculations, because its ET rates can be calculated without adjustable parameters. Our absolute rate calculations are in an order-of-magnitude agreement with the experimental ones.