Quantum Interference Effects in Self-Assembled Asymmetric Disulfide Monolayers:  Comparisons between Experiment and ab Initio/Monte Carlo Theories

• Published in: The journal of physical chemistry. B Vol. 101; no. 6; pp. 1058 - 1062
• Main Authors: Cheng, Jun, Miller, Cary J
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06-02-1997
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp962731k

Electron transfer measurements between solution redox probes and a Au electrode coated with self-assembled monolayers of symmetric and asymmetric ω-hydroxyalkane disulfides are used to probe the quantum interference between hydrocarbon chains of different lengths. While ab initio theory predicts a measurable destructive interference effect between hydrocarbon chains differing in length by a single methylene unit, electron transfer rates for the ferricyanide and horse heart cytochrome c are more consistent with rates estimated in the absence of the interference effect. The discrepancy between theory and experiment is discussed in light of possible interchain electronic coupling and phase segregation within the monolayers and limitations of the theoretical models.