Odd-Even Effect on Supramolecular Co-Assemblies: Control over the Two-Dimensional Self-Assemblies of a Fluorenone Derivative with Asymmetrically Substituted Alkyl Chains

Abstract

The precise control of two-dimensional supramolecular co-assemblies presents a research topic related to advance nanotechnology. Here, we report a scanning tunneling microscopy (STM) study of the mixture behavior of three fluorenone derivatives at the liquid–solid interface. The target molecule is F–C12C13 whose structure bears asymmetrical alkyls, whereas the regulating molecules, either F–C12C12 or F–C13C13, are structurally symmetric. By STM imaging of systematic mixtures with various volumes among the sample solutions, we found that the mixing ratio mainly determined the binary outcomes. Compared with F–C12C12, F–C13C13 shows a stronger ability to dominate the patterning, explained by the larger binding and adsorption energies calculated by the force field simulations. Moreover, the odd-even effect exists in the system. Overall, we acquired knowledge about the regulating ability of bi-component supramolecular assembling, especially for structurally asymmetric molecular systems.

Two-dimensional molecular networks at the solid/liquid interface and the role of alkyl chains in their building blocks

“…In addition, similar alkyl chain-related effects, including the odd-even effect, have been also reported for fluorenone derivatives [141,142].…”

“…Other substitution effects, such as different substitution positions with two and three alkyl chains, were reported by the same group [ 139 – 140 ]. In addition, similar alkyl chain-related effects, including the odd–even effect, have been also reported for fluorenone derivatives [ 141 – 142 ].…”

Tuning Preferential Molecular Adsorption and Self-Assembled Molecular Network Formation at the Liquid–Solid Interface: The Impact of Annealing and Confinement

“…Self-assembly of organic molecules in two dimensions (2D), i.e., the formation of self-assembled molecular networks (SAMNs), on solid surfaces such as highly oriented pyrolytic graphite (HOPG), gold, silver, and other metals is a promising method for constructing well-defined patterns at the molecular level, with a high level of control. − This has attracted the interest from diverse areas ranging from supramolecular chemistry to nanoscience and nanotechnology. − The potential of the approach to engineer surfaces and interfaces holds promise for applications in fields as diverse as electronics, sensing, and tailored catalysis. − These SAMNs formed on a conductive solid surface are usually investigated using scanning tunneling microscopy (STM), either at ambient or under ultrahigh-vacuum conditions. − This research field has witnessed rapid development in understanding how molecular and interfacial interactions can influence the arrangement of molecules. Diverse nanostructures have been realized ranging from monolayers to bilayers or multilayers, from monocomponent linear architectures to multicomponent host-guest porous networks, and many others. − …”

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We report on the selective adsorption and the formation of self-assembled molecular networks (SAMNs) at the interface between a liquid and highly oriented pyrolytic graphite (HOPG) from equimolar mixtures of alkoxylated dehydrobenzo [12]annulene (DBA) derivatives 11,or 16]) that differ in the length of their six alkoxy chains. As revealed by scanning tunneling microscopy at the liquid−solid interface on pristine HOPG at room temperature, every component in the mixtures forms separate domains, where the larger molecules tend to occupy the larger surface area.

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Breaking Radial Dipole Symmetry in Planar Macrocycles Modulates Edge‐to‐Edge Packing and Disrupts Cofacial Stacking

“…Zimmt [19b–f] designed long alkane chains with dipolar ketone (2.6 Debye) and ether (1.2 Debye) groups to investigate the competition between dipolar and van der Waals interactions. Deng [19a,20] analyzed the cooperation of dipolar and van der Waals interactions on the 2D self‐assembly of fluorenone derivatives bearing side chains with dipolar ester groups (2 Debye) by varying the alkyl length. Deng also analyzed such cooperation of dipolar and van der Waals interactions on the 2D self‐assembly with benzothiadiazole [21] and diaminotriazine [22] derivatives.…”