Electron Tunneling through Rigid Molecular Bridges: Bicyclo[2.2.2]octane

Electron tunneling through polymers of bicyclo[2.2.2]octane is studied. The repeating nature of the linker allows prediction of the dependence of the tunneling matrix element on distance and electronic energy by a semiempirical method exploiting the translational symmetry of the linker. Specific predictions for the dependence of rate on distance are made for recently synthesized photosynthetic model compounds containing porphyrins and quinones linked by this bridge. A large difference between the decay of rate with distance is predicted for the forward electron transfer in these model compounds compared with the reverse electron transfer. The effects of linker topology on the donor-acceptor interaction in several linkers are compared, and a heuristic rule is quantitated. The ability of the [2.2.2] linker to mediate the donor-acceptor interaction is shown to have an energy dependence determined by the symmetry of the donor and acceptor orbitals relative to the linker orbitals. © 1986, American Chemical Society. All rights reserved.

Duke Scholars

Author David N. Beratan Chemistry