STM investigations of physisorbed monolayers of dialkoxy-substituted aromatics

Directing the Assembly of Gold Nanoparticles with Two-Dimensional Molecular Networks

“…The SAMN contains one molecule per unit cell ( a = 2.1 ± 0.1 nm, b = 1.0 ± 0.1 nm, and α = 86 ± 1°, plane group p 2), with the lamellae width (2.1 ± 0.1 nm) defined by fully extended and interdigitated decyloxy substituents. This packing, frequently reported for the assembly of alkylated aromatic molecules on HOPG, − is driven mainly by the attractive lateral interaction between alkoxy chains and the in-registry adsorption of alkoxy chains along one of the principal axes of the HOPG lattice.…”

“…p -Dialkoxybenzene derivatives are among the simplest and most synthetically versatile compounds fulfilling these requirements (Scheme ). Two alkoxy chains provide strong vdW stabilization of the 2D molecular pattern at an HOPG surface. − The periodicity of such a pattern can be controlled by the length of the alkyl groups (decyl vs octadecyl). The aromatic core enables facile introduction of various functionalities, such as thiol sites for potential binding to AuNPs (while the use of free dithiols in air is problematic due to oxidative polymerization, acetyl-protected thiols have also been shown to form RS-Au bonds) …”

“…These correspond to the aromatic core and alkyl chains, respectively, in accord with previous observations in similar SAMNs (Figure ). − …”

Chain-Length Effects on Molecular Conformation in and Chirality of Self-Assembled Monolayers of Alkoxylated Benzo[c]cinnoline Derivatives on Highly Oriented Pyrolytic Graphite

“…The self-assembly of molecules at surfaces is a spontaneous process from disorder to order that involves a balancing of the forces between molecules and substrates. Self-assembled monolayers (SAMs) at solid surfaces offer many potential applications in industry and might be widely used in future nanotechnologies. − To control the 2-dimensional (2D) structures, scientists have made tremendous efforts toward understanding the formation mechanisms of SAMs by varying the assembly approaches, − solvents used, , and substitution groups − of the parent molecules, for example.…”

“…To date, a variety of SAMs of organic or inorganic molecules at surfaces have been reported. − In principle, with a proper balance of the weak forces arising from intermolecule and molecule−substrate interactions, physically adsorbed molecules on HOPG can self-assemble into a highly ordered 2D structure. Many researchers have tried to tweak these weak forces by finely tuning the molecular backbones to see how the self-assembled structures changed. − The accumulated knowledge and experience in such studies were, in turn, used to predict self-assembled structures of similar molecules. This approach is quite reasonable, but not necessarily always right.…”