An extension of the McConnell superexchange formula to the case of real conjugated oligomers

The McConnell formula of superexchange that describes the long-range, non-adiabatic bridge-mediated electron transfer (ET) is generalized to the case of conjugated bridges covered by the structural formula M–M–…–M, where M is an arbitrary monomer. An explicit definition of the exponential decay constant and pre-exponential factor (in the standard expression of the ET rate) is given in terms of the monomer Greenʹs function. This makes it possible to address the essentials of electron transfer across large molecules at the monomer level. The obtained dependence of the ET rate on parameters of the bridge electronic structure is compared with the original McConnell result and exemplified by analytical expressions of the effective donor–acceptor through-bridge coupling for oligomers of polyene and five- and six-membered aromatic ring based oligomers.