ELECTRONIC FACTOR FOR ELECTRON-TRANSFER THROUGH CYCLOHEXANE-TYPE SPACERS

The electronic factor DELTA for electron transfer is calculated for a number of donor-acceptor systems of the general type D- B A --> D B A- and D B A+ --> D+ B A using ab initio methods. B is cyclohexane-type spacer which is bonded to the donor D and the acceptor A. All geometries have been optimized for the neutral system obtain a good agreement with the experimental results of Closs, Miller, and co-workers with an exponential decrease of DELTA as a function of distance R between D and A. In some other systems, where experimental results are not available, we obtain a nonexponential DELTA(R) with a change of sign between three and four spacer units.