Theoretical Interpretation of Conductivity Measurements of a Thiotolane Sandwich. A Molecular Scale Electronic Controller

Abstract

Quantum density functional theory and classical molecular dynamics studies of tolane molecules are carried out to interpret results of conductivity measurements on a monolayer of thiotolane molecules self-assembled on a gold surface and sandwiched by a titanium layer. Density functional theory techniques have been used to determine the ground state conformations and electronic structure, while classical molecular dynamics accounts for the effects of pressure and temperature for a cluster of five thiotolane molecules arranged between titanium and gold surfaces used to simulate the experimental system. On the basis of the theoretical results, it can be concluded, in agreement with the experimental findings, that the relative angle between two benzene rings in each tolane molecule determines its conductivity, with a maximum at 0° and a minimum at 90°. Therefore, this system would work as an unbiased controller, where the current through the molecule is controlled by the angle of one phenyl ring with respect to the other.

Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene)

“…In this geometry, the p-faces of the polymer main chain are oriented parallel to each other, so that a considerable p-p-interaction of the aromatic rings occurs. The benzene rings of different chains in one lamella must be offset according to the Tour-Seminario model 18) . Interaction of the ordered polymer chains (approximately 4.2 Å separated) must be the reason for the observation of the extremely well-resolved aggregate band in both CH 3 OH/CHCl 3 mixtures and in the solid state.…”

Molecular, Supramolecular, and Macromolecular Motors and Artificial Muscles

“…3,27,32,33 All of these favorable features make alkanethiolate monolayers well suited for serving as host matrices for insertion of target molecules. [34][35][36] Figure 1a schematically shows the process of inserting guest molecules into an n-alkanethiolate SAM on Au{111}, which serves as the substrate surface for the formation of SAM, the physical support and connection, and one of the electronic contacts. Figure 1b shows a molecularresolution scanning tunneling microscopy (STM) image of a typical alkanethiolate SAM, in which a number of different types of defects, including domain boundaries, step edges, gold substrate vacancy islands, and disordered SAM regions, are observed.…”

Synthesis and Characterization of Conjugated Mono- and Dithiol Oligomers and Characterization of Their Self-Assembled Monolayers

“…With the advent of research activities in nanoscale molecular electronic devices, [1][2][3][4][5][6][7][8] organic thiol compounds have received a great deal of attention in recent years, 9,10 because of their intrinsic semiconductor [11][12][13][14][15][16] or insulator [17][18][19][20][21] properties. Conjugated thiol-capped compounds such as oligo(1,4-phenylene ethynylene)s and oligo-(2,5-thiophene ethynylene)s have been widely studied as molecular wires.…”