Formation of multicomponent 2D assemblies of C 2v-symmetric terphenyl tetracarboxylic acid at the solid/liquid interface: recognition, selection, and transformation

The self-assembly of a pair of low-symmetry tetracarboxylic acid molecules and their co-assembly with bridging molecules at the liquid-solid interface

The supramolecular self-assembly behavior of a pair of low-symmetry tetracarboxylic acid molecules (H₄OBDB and H₄ADDI) and their co-assembly behavior with TMA as a bridging molecule were studied at the liquid-solid interface. Scanning tunneling microscope (STM) observations revealed that H₄OBDB and H₄ADDI molecules both tend to form O-shaped dimers but end up forming different types of self-assembly structures. We also investigated the construction of two-component co-assembly structures by mixing H₄OBDB or H₄ADDI molecules with bridging molecules such as TMA. The two formed co-assembly structures are similar. Based on the analysis of the STM results and the density functional theory (DFT) calculations, the formation mechanism of the assembled structures was revealed.

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

The supramolecular self-assembly behavior of a low-symmetric aromatic carboxylic acid molecule (H₅BHB) and its co-assembly behavior with a series of pyridine molecules (BPD, BPDYB and TPDYB) were studied at the heptanoic acid/HOPG liquid-solid interface. Scanning tunneling microscopy (STM) observations revealed that H₅BHB molecules tend to form dimeric building blocks which then assemble into a close-packed structure. BPD, BPDYB and TPDYB pyridine molecules were all able to form a stable two-component co-assembled structure with the H₅BHB molecule, and in these co-assembled structures, the H₅BHB molecule still takes the form of a dimer. It was found that the pyridine molecules were able to regulate the self-assembly structure of the H₅BHB molecule, and the molecular arrangement of the co-assembly structures varies with the shape of the pyridine molecules. Based on the analysis of the STM results and density functional theory (DFT) calculations, the formation mechanism of the assembled structures was revealed.

Self-assembled flower structures formed by C3-symmetric aromatic carboxylic acids with meta-carboxyl groups

H₆BTE self-assembled into flower-like structures with two types of cavities at the HA/HOPG interface, and the guest molecule COR was only trapped in the A-type cavities at low and high concentrations of COR.