Principles of molecular assemblies leading to molecular nanostructures

Abstract

Self-assembled physisorbed monolayers consist of regular two-dimensional arrays of molecules. Two-dimensional self-assembly of organic and metal–organic building blocks is a widely used strategy for nanoscale functionalization of surfaces. These supramolecular nanostructures are typically sustained by weak non-covalent forces such as van der Waals, electrostatic, metal–ligand, dipole–dipole and hydrogen bonding interactions. A wide variety of structurally very diverse monolayers have been fabricated under ambient conditions at the liquid–solid and air–solid interface or under ultra-high-vacuum (UHV) conditions at the UHV–solid interface. The outcome of the molecular self-assembly process depends on a variety of factors such as the nature of functional groups present on assembling molecules, the type of solvent, the temperature at which the molecules assemble and the concentration of the building blocks. The objective of this review is to provide a brief account of the progress in understanding various parameters affecting two-dimensional molecular self-assembly through illustration of some key examples from contemporary literature.

Kinetic and thermodynamic processes of organic species at the solution–solid interface: the view through an STM

“…The estimation of the ''dewetting'' term is the most difficult. 1,2,20,25 In some cases, these polymorphs can be traced to differing amounts of coadsorption of solvent. Thus, the heats of wetting for the solvent on the substrate are overestimates of the net result of the multistep step ''dewetting''.…”

“…[1][2][3][4][5][6] To date, most variable temperature and composition STM studies at the solid-solution interface have been performed with home made or commercial instruments using heated (only) samples. Molecular self-assembly from solution onto surfaces is widely embraced as a strategy for creating adlayers with desirable electronic, photonic, and chemical properties.…”

“…Thus, STM has become the primary tool for analyzing structure, monitoring the time dependence of processes, and extracting thermodynamic data from systems where the critical action occurs at the nanoscale. [1][2][3][4][5][6] To date, most variable temperature and composition STM studies at the solid-solution interface have been performed with home made or commercial instruments using heated (only) samples. [7][8][9] Very recently an alternative configuration wherein the entire STM exists in a controlled environment has been demonstrated.…”

Role of the Metal Surface on the Room Temperature Activation of the Alcohol and Amino Groups of p-Aminophenol

“…11 This adsorption mechanism will define the chemical reactivity of the precursor molecules on a specific surface determining the properties and the structure of the final outcome. 12 To date, some studies have been already reported to demonstrate a different behavior of the same molecule adsorbed on different surfaces, highlighting the role of the surface in the process. Examples of this observed behavior are the cases of perylenetetracarboxylic dianhydride (PTCDA), benzene, and porphyrins, among others, in which different properties have been observed as a consequence of the different geometrical adsorptions.…”

Seeding Chiral Ensembles of Prolinated Porphyrin Derivatives on Glass Surface: Simple and Rapid Access to Chiral Porphyrin Films

“…The challenging stage for the drop-casting production of chiral solid films is surely the identification of the proper solvent to use for the stock solution. As reported in the literature, the nature of the solvent used is extremely relevant to define the structures that the layers adopt and the overall chirality (Iavicoli et al, 2009;Chen et al, 2019), since both derive from a combination of the interaction strength of the molecules with the surface and their solubility (Zaera 2009;Mali and De Feyter, 2013). Moreover, solvent parameters like viscosity, surface tension, and vapor pressure strictly impact the film adhesion to the substrate and the evaporation rate, producing layers featuring different structural motifs and homogeneity (Resedean et al, 2020).…”