A highly ordered, aromatic bidentate self-assembled monolayer on Au(111): a combined experimental and theoretical study

Abstract

Self assembled monolayers (SAMs) made from an aromatic organodithiol, 2-mercaptomethylbenzenethiol (C(6)H(4)SHCH(2)SH) on Au(111) have been investigated in the context of a combined experimental and theoretical approach. The SAMs prepared by immersion of an Au-substrate in corresponding ethanolic solutions were characterized using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRRAS) and thermal desorption spectroscopy (TDS). Adapted from the experimentally obtained unit cell of the SAM, density functional theory (DFT) calculations were applied to get a deeper insight into the structure of these dithiolate based SAMs. On the basis of the experimental and theoretical findings we provide a detailed structural model for this aromatic SAM consisting of the phenyl-group rigidly anchored to the substrate by two thiolate-bonds.

Substituent-Controlled Reversible Switching of Charge Injection Barrier Heights at Metal/Organic Semiconductor Contacts Modified with Disordered Molecular Monolayers

“…In addition, dithiol molecules are known to form DM with higher disorder than that of DM formed by their monothiol counterparts. 29 A well-ordered SAM structure is formed by the adsorption and subsequent surface diffusion of the molecules. Two binding groups enable the molecules to strongly bind to the electrode surface, inhibiting the surface diffusion of the molecules.…”

“…Dithiol molecules are known to form DMs with higher disorder than their monothiol counterparts. 29 As a result, the B2T DM should have lower structural stability than the BT DM.…”

Effects of Introducing 2-aminoethanethiol into 4-pyridineethanethiol Self-assembled Monolayer Applicable to Enhance Sensitivity of Hg(II) Electrochemical Analysis

“…Fig. 3 shows FTIR spectra of different SAMs with most prominently visible bands corresponding assignments based on literatures [30][31][32][33]. Briefly, bands at 868, 1090, 1179, 1297, and 1496 cm -1 are assigned to (C-H) wagging, CH 2 wagging + (C-C) ring bending, CH 2 wagging + (C-H) ring deformation, (C-H) ring deformation + (C-N) stretching, and (C-C) ring + (C-H) ring deformation.…”

Caracterización y modelado de superficies de Au(111) y Au(100) recubiertas con tioles de interés biológico

“…En este sentido, se conoce que el nivel de orden que adquieren las moléculas al quimisorberse sobre una superficie metálica depende de su capacidad para difundir sobre la misma. 112,113 La forma de la molécula 114 y su capacidad de enlazarse a la superficie a través del número de grupos funcionales que presenta influyen en la capacidad de difundir sobre la superficie. En el caso de la 6MP, la forma elipsoidal que posee hace más difícil los movimientos rotacionales necesarios para desplazarse.…”

“…Esta situación es similar a lo que ocurre con los ditioles que se enlazan mediante dos uniones S al Au(111) y cuyas SAMs presentan alto grado de desorden. 112 Además se ha observado que las SAMs de tioles heterocíclicos como el 2mercaptoimidazol, el 2-mercaptobenzotiazol y el mercaptobenzoxazol, los cuales además del enlace tiolato tienen también otra interacción adicional con el Au(111) a través del N, S u O, respectivamente, presentan alto grado de desorden molecular. 115 Podría argumentarse que el menor cubrimiento que alcanzan estas moléculas sobre el Au(111) influye aumentando el grado de desorden, pero el ácido 4-mercaptobenzoico en la cara Au(111) alcanza una organización molecular de largo alcance con un cubrimiento similar al de la 6MP.…”