Molecular trapping in two-dimensional chiral organic Kagomé nanoarchitectures composed of Baravelle spiral triangle enantiomers

Abstract

The supramolecular self-assembly of a push-pull dye is investigated using scanning tunneling microscopy (STM) at the liquid-solid interface. The molecule has an indandione head, a bithiophene backbone and a triphenylamine-bithiophene moiety functionalized with two carboxylic acid groups as a tail. The STM images show that the molecules adopt an "L" shape on the surface and form chiral Baravelle spiral triangular trimers at low solution concentrations. The assembly of these triangular chiral trimers on the graphite surface results in the formation of two types of chiral Kagomé nanoarchitectures. The Kagomé-α structure is composed of only one trimer enantiomer, whereas the Kagomé-β structure results from the arrangement of two trimer enantiomers in a 1:1 ratio. These Kagomé lattices are stabilized by intermolecular O-H•••O hydrogen bonds between carboxylic acid groups. These observations reveal that the complex structure of the push-pull dye molecule leads to the formation of sophisticated two-dimensional chiral Kagomé nanoarchitectures. The subsequent deposition of coronene molecules leads to the disappearance of the Kagomé-β structure, whereas the Kagomé-α structure acts as the host template to trap the coronene molecules.

The self-assembly and pyridine regulation of a hydrogen-bonded dimeric building block formed by a low-symmetric aromatic carboxylic acid

“…26 Dong et al recently reported a low-symmetric push–pull dye molecule containing two carboxylic acid groups self-assembled into chiral triangular trimers adopting a Baravelle spiral triangle arrangement. 27 Considering that the self-assembly of low symmetric carboxylic acid molecules has not been fully studied and is capable of forming a variety of specific nanostructures, a low-symmetric aromatic penta-carboxylic acid (H 5 BHB) has been studied in our study. The chemical structure of H 5 BHB is presented in Scheme 1; the molecular skeleton of H 5 BHB is the same as that of the symmetric tricarboxylic acid BTB, except that two of the 4-carboxyphenyl groups of BTB are replaced by 3,5-dicarboxyphenyl groups.…”

Coronene and Phthalocyanine Trapping Efficiency of a Two-Dimensional Kagomé Host-Nanoarchitecture

“…These trimers are composed of blue-, red- and green-colored molecules in Figure 2 b,c. A model of the molecular arrangement is presented in Figure 2 c [ 34 ]. Molecules do not adopt a straight conformation but an “L” conformation.…”

“…Solution of coronene at a low concentration (2.0 × 10 −6 M), also in 1-octanoic acid, was prepared. to trap round coronene molecules at high concentration [34]. However, the ability of a host structure has to be assessed at low guest-molecule concentration to determine its efficiency and stability.…”

“…We recently successfully engineered a porous two-dimensional (2D) Kagomé hostnanoarchitecture through the self-assembly of "push-pull" dyes and used this structure to trap round coronene molecules at high concentration [34]. However, the ability of a host structure has to be assessed at low guest-molecule concentration to determine its efficiency Nanomaterials 2022, 12, 775 2 of 10 and stability.…”

Solvent-Dependent Molecular Isomerization and 2D Self-Assembled Phase Transitions of Benzothiadiazole-Based π-Conjugated Fluorophore

“…Organic semiconductor materials based on π-conjugated benzothiadiazole-based (BTD) chromophores have received significant research interest in recent years because of their promising performance in organic photovoltaic cells (OPVs), , organic light-emitting diodes (OLEDs), , organic field-effect transistors (OFETs), and others. , The performance of organic electronic devices depends on the photophysical properties of π-conjugated materials . Apart from their chemistry structures, the supramolecular arrangement in solid states can drastically affect their photoelectric properties. − It is thus necessary to investigate the molecular arrangement of adlayers. Self-assembly is the on-surface bottom-up method to acquire novel organic nanoarchitectures. , In practice, the self-assembly behavior in thin films is of vital importance because the self-assembly modes play dominated roles in their electrical transport properties as well as other properties such as anisotropic character. , The self-assembled nanostructures are stabilized by a delicate balance which is affected by internal factors including intermolecular interactions , and external factors such as solvent , and solution concentration .…”