STM Study of the Self-Assembly of Biphenyl-3,3′,5,5′-Tetracarboxylic Acid and Its Mixing Behavior with Coronene at the Liquid–Solid Interface

Abstract

We report a scanning tunneling microscopy (STM) study of the molecular self-assembly of biphenyl-3,3′,5,5′tetracarboxylic acid (BPTC) at the octanoic acid/graphite interface. STM revealed that the BPTC molecules generated stable bilayers and monolayers under high and low sample concentrations, respectively. Besides hydrogen bonds, the bilayers were stabilized by molecular π-stacking, whereas the monolayers were maintained by solvent co-adsorption. A thermodynamically stable Kagoméstructure was obtained upon mixing BPTC with coronene (COR), while kinetic trapping of COR in the co-crystal structure was found by the subsequent deposition of COR onto a preformed BPTC bilayer on the surface. Force field calculation was conducted to compare the binding energies of different phases, which helped to provide plausible explanations for the structural stability formed via kinetic and thermodynamic pathways.

Study on 2D Molecular Networks of Flexible Pentacarboxylic Acid Ligands Induced by Ether Bonds in Response to Selective Guest Inclusion

“…Based on this design, a series of linear rigid carboxylic acid derivatives were synthesized, forming dense packing, parallel, and Kagomé nanostructures through hydrogen bonding on solid surfaces . These supramolecular network structures on solid surfaces offer the possibility of fixing and identifying functional guest molecules in spatially ordered arrangements, in which carboxylic acid molecules play as a template to capture different guest molecules; − for example, the 1,3,5-tris­(10-carboxy­decyloxy)­benzene (TCDB) molecule has proved to be a useful molecular template that can accommodate functional molecules such as COR, triphenylene, phthalocyanine, and so on. − Additionally, guest molecules could induce the transformation of the host carboxylic derivatives’ assembled structures. − For example, Beton et al used the COR guest template to guide the formation of a two-dimensional Kagomé network, replacing the original dense packing and parallel hydrogen bond structure formed by self-assembly on the graphite surface . These host–guest behaviors depend on the host molecules’ cavity properties, such as size, shape, and symmetry, as well as the type of guest molecules …”

On-Surface Molecular Recognition Driven by Chalcogen Bonding

“…The manipulation of organic nanostructures on surfaces through the supramolecular approach has garnered substantial attention in recent decades. − Among the various supramolecular interactions, H-bonding interactions have been extensively harnessed to foster the formation of highly organized two-dimensional (2D) networks. − This has been followed by examples reporting coordination bonding − and dipole–dipole , interactions (Figure a–c). More recently, there has been a notable surge of interest in employing secondary bonding interactions (SBIs), which have a dual nature.…”

Steering the Surface-Confined Self-Assembly of Multifunctional Star-Shaped Molecules

“…These alveolate sectors, known as pores or cavities, can be fine-tuned to serve as well-defined matrices for the positioning and spatial organization of guest atoms/molecules. They can also act as 2D sieves, allowing size/shape segregation of mixed chemical entities, or as nanometer-sized reactors. − Additionally, due to the confinement of the molecules in a plane and their vertical interaction with the substrate, the flat-lying admolecules lose conformational freedom and may exist in the form of one, two, , or few surface conformers. , This fact is of great importance as the final outcome of the surface-supported SA is usually much more predictable and controllable than the analogous processes occurring in the bulk. Furthermore, the supramolecular architectures comprising laterally interconnected admolecules can be visually inspected by means of high-resolution scanning tunneling microscopy (STM) and other advanced non-destructive techniques, which strongly facilitates their structural analysis .…”