Abstract

It is well known that the rate of intramolecular electron transfer in linked donor-acceptor molecules is not only dependent upon the distance and orientation between the donor (D) and acceptor (A), but is also dependent upon the electronic properties of the intervening spacer (S) molecules between the redox centers[1]. If the distance between D and A is small enough to allow for direct overlap between the frontier orbitals of the donor and acceptor, electron transfer may occur by means of a through-space mechanism. When the D and A centers are too far apart for direct orbital overlap to be important, electron transfer may occur via a superexchange or through bond interaction. Both contributions to the total electronic coupling matrix element for electron transfer between the donor and acceptor depend on the distance and the orientation of the various molecular components. Thus, it is important to hold both the distance and geometry of the donor and acceptor fixed as the properties of the covalent spacer between them are varied. Achieving this degree of structural control in a D-S-A molecule is often a difficult task.

© 1996 Optical Society of America