Anomalous Distance Dependence of Electron Transfer across Peptide Bridges

The first investigation on the distance dependence of a dissociative electron transfer process across peptide bridges is reported. This study was carried out by using a series of donor−peptide−acceptor systems in which the donor is a phthalimido moiety, the peptide bridges are provided by α-aminoisobutyric acid (Aib) homooligomers, and the acceptor is a peroxide functional group. The intramolecular electron transfer from the electrogenerated phthalimido radical anion to the peroxide was studied in comparison with the thermodynamic and kinetic information obtained with models of the acceptor and the donor.