Single-molecule Conductance and Electrochemical Measurements of Electron Transfer in β-strand Peptides

A series of beta-strand peptides comprising redox-active amino acids in the P2 position were synthesized to investigate the effects of electron-rich side chains on charge transfer and possible coupling interactions between side chains. Electrochemical results indicated a direct link between aromaticity of the side chains and electron transfer rate constants, while single-molecule conductance studies supported the ability of the electron-rich side chains to behave as 'stepping stones' to facilitate electron transfer through the peptides. Additional electrochemical analysis of the analogue containing D-Tyr in the P2 position was undertaken at various pH levels and revealed intramolecular coupling interaction between the side chains, providing further insights on proton coupled electron transfer (PCET). These findings progress the established fundamental knowledge of charge transfer kinetics and explore new pathways for advancement in the architecture of molecular-based electronic components and devices.