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0,440,400,36E 1/ 2(V vs SCE)0,320,280,240,200,161 2 3 4 5n- AibFig. 2. Redox potentials vs SCE of the Fc-CO-(Aib) n -OMe (n=1-5) peptide seriesrecorded at a 0.5 mm diameter gold disk electrode in CH 2 Cl 2 with 0.1 M nBu 4 NPF 6 assupporting electrolyte.The effect of the different orientation of the dipole moment (the latter increasing with thenumber of Aib residues in the backbone) was investigated by means of electrochemical andspectroscopic techniques. The oxidation potential dramatically depends on the dipoledirection and the number of Aib units (the latter tunes intramolecular hydrogen-bondformation) (Figures 1 and 2). Moreover, the dependence of current intensity on peptidelength was also explored. Finally, the shift and pattern of the C=O and N-H vibrations uponoxidation were used for mapping charge delocalization in the peptide chains, andestimating efficacy and time scale of intramolecular ET.References1. Karle, I.L., Balaram, P. Biochemistry 29, 6747-6756 (1990).2. Toniolo, C., Benedetti, E. Macromolecules 24, 4004-4009 (1991).585