Electronic excitation and electric field as switching mechanism for a single-molecule switch

Abstract

DFT calculations show that a combination of an electric field and electronic excitation is a promising mechanism to force a molecular switch based on amino-imino tautomerisation into one of its two states. By calculating the effect of an electric field in the direction of the moving hydrogen on the shape of the barrier in the ground and low-lying excited states of previously proposed molecular switches consisting of 5- and 7-membered rings with adjacent amino and imino groups, we demonstrate that electric fields and photons in experimentally accessible ranges introduce sufficient asymmetry to push the switch into the desired configuration. Excitation to states with inverted order of the preferred geometry allows reversible switching without reversal of the electric field.

GRAPHICAL ABSTRACT

KEYWORDS:

• Molecular switch
• excited states
• electric field
• density functional theory
• molecular electronics

Acknowledgements

We thank EaStCHEM for computer resources supplied by the EaStCHEM Research Computing Facility.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Supplementary Materials: Figure S1: Relative energies of the ground state and five or six low-lying excited states of the 5-ring and 7-ring both with ethyne wires attached, as a function of the reaction coordinate. Table S1: Xyz files of the optimised 5-ring and 7-ring mimina and transition states with and without molecular wires. The research data supporting this publication can be accessed at https://doi.org/10.17630/fda73ef0-9944-4531-aed6-90b5c14a411a.