Triptycene-terminated thiolate and selenolate monolayers on Au(111)

Abstract

To study the implications of highly space-demanding organic moieties on the properties of self-assembled monolayers (SAMs), triptycyl thiolates and selenolates with and without methylene spacers on Au(111) surfaces were comprehensively studied using ultra-high vacuum infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy and thermal desorption spectroscopy. Due to packing effects, the molecules in all monolayers are substantially tilted. In the presence of a methylene spacer the tilt is slightly less pronounced. The selenolate monolayers exhibit smaller defect densities and therefore are more densely packed than their thiolate analogues. The Se-Au binding energy in the investigated SAMs was found to be higher than the S-Au binding energy. 892

Triptycene Tripods for the Formation of Highly Uniform and Densely Packed Self-Assembled Monolayers with Controlled Molecular Orientation

“…Because of the 3-fold symmetry of T1 and T2 , the average value of the molecular tilt angle (β) can be directly obtained from the dependence of the intensity of the π 1 * resonance on cos 2 θ. 30 The resulting values of β are shown in Table 1, along with the value for the B1 /Au SAM. The latter can, however, only be considered as a lower limit of the average tilt angle in that system due to the lower molecular symmetry, which results in a dependence of the calculated value of β on the molecular twist (here set to 0° yielding the minimum value of β for a given α).…”

“…Notably, due to the tridentate configuration, the present systems differ distinctly from previously reported monodentate triptycene-based monolayers with a single thiol or selenol group attached in the bridgehead position. 29,30 There, the triptycene moieties are prone to adopting a substantially tilted configuration.…”

Tetrapodal Diazatriptycene Enforces Orthogonal Orientation in Self-Assembled Monolayers

“…Among rigid scaffolds, thiol-substituted triptycenes have been used on gold surfaces. [43][44][45] Examples include porphyrins, 46-48 resorcin[4]arenes, 49 as well as fluorene 50 and carbazole-based 51…”

Influence of a Metal Substrate on Small‐Molecule Activation Mediated by a Surface‐Adsorbed Complex

“…In the case of porphyrins, interaction of the complex with the surface is reduced on binding of a ligand trans to the surface . This is avoided if the molecules are covalently attached to the surface, for example, by a thiol group to Au(111), as shown in Figure b . In this case, however, the orientation of the complex with respect to the surface is less defined.…”

“…[33] This is avoided if the molecules are covalently attached to the surface, for example, by at hiol group to Au(111), as shown in Figure 1b. [35,36] In this case, however,t he orientation of the complex with respect to the surface is less defined. Thec omplex may also be clicked to as elfassembled monolayer (SAM) that has first been depositedo n the metal surface.…”