Insertion, Conductivity, and Structures of Conjugated Organic Oligomers in Self-Assembled Alkanethiol Monolayers on Au{111}

M. T. Cygan, T. D. Dunbar, J. J. Arnold, L. A. Bumm, N. F. Shedlock, T. P. Burgin, L. Jones II, D. L. Allara,* J. M. Tour,* and P. S. Weiss*

Submitted to Journal of the American Chemical Society.

Abstract

Alkanethiolate self-assembled monolayers on Au{111} are used for the two-dimensional matrix isolation of conjugated organic thiolates, studied for their potential to act as molecular wires. The conjugated organic molecules are inserted from dilute solution into boundaries between structural domains and at substrate step edges of pre-assembled n-alkanethiolate monolayers so as to preserve the order of the initial alkanethiolate lattice. In contrast, when both molecules are co-deposited from a single solution, the structure of the assembled monolayer shows no ordered molecular lattice of the alkanethiol component. Scanning tunneling microscopy measurements on the isolated conjugated component molecules shows them to have enhanced conductivity compared to neighboring alkanethiolates.