Frontier Orbital Control of Molecular Conductance and its Switching1. Issue 16 (12th March 2014)

• Record Type: Journal Article
• Authors: Tsuji, Yuta; Hoffmann, Roald
• Is Part Of: Angewandte Chemie international edition. Volume 53:Issue 16(2014)
• Page Start: 4093
• Page End: 4097
• Publication Date: 2014-03-12
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201311134
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>For transmission of electrons through a π system, when the Landauer theory of molecular conductance is viewed from a molecular orbital (MO) perspective, there obtains a simple perturbation theoretic dependence, due to Yoshizawa and Tada, on a) the product of the orbital coefficients at the sites of electrode attachment, and b) the MO energies. The frontier orbitals consistently and simply indicate high or low transmission, even if other orbitals may contribute. This formalism, with its consequent reinforcement and/or interference of conductance, accounts for the (previously explained) difference in direct vs. cross conjugated transmission across an ethylene, as well as the comparative ON/OFF ratios in the experimentally investigated dimethyldihydropyrene and dithienylethene‐type single‐molecule switches. A strong dependence of the conductance on the site of attachment of the electrodes in a π system is an immediate extrapolation; the theory then predicts that for some specified sites the switching behavior will be inverted; i.e. the "open" molecular form of the switch will be more conductive.</p> </abstract>