F···Br and F···S Heterohalogen-Bond-Directed 2D Self-Assemblies of a Benzothiadiazole Derivative

Abstract

Halogen bonding (XB) is of great importance in fabricating a two-dimensional (2D) self-assembly for its adaptive directionality. However, the XBs involving fluorine (F) have barely been studied due to the absence of an σ-hole on F. Here, 2D selfassemblies of a F-substituted 4,7-bis(5-bromo-4-dodecylthiophen-2-yl)-5,6-difluorobenzo [c][1,2,5]thiadiazole (BTZ-BrF) molecule on graphite were investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. STM experiments revealed that the 2D patterns of BTZ-BrF had a clear solvent and concentration dependence, showing a frame-like pattern in aliphatic acid and aliphatic hydrocarbon solvents at high concentrations. At lower concentrations, a bamboo-like and a wave-like pattern were observed in aliphatic acid, whereas small frame-like and large ladder-like domains at high solution concentrations in aliphatic hydrocarbon were observed. As the concentration further decreased, two linear patterns were observed. DFT calculations suggested that the hetero-XBs of Fand Br•••N, the homo-XBs of type-II Br•••Br, and the S•••S interactions synergistically directed and stabilized the polymorphic 2D architectures. This understanding of intermolecular XBs during the molecular assembly at the molecular level may shed light on the ongoing efforts of regulating nanostructures of multifunctional organics.

Structural and Magnetic Properties of a Drop-Cast C54H34Br4CuO4 β-Diketonato Complex Film on a Graphite Surface

“…Selective and directional intermolecular interactions allow one to control the molecular assembly into specific arrangements. Large-scale 2D self-assembled organic nanoarchitectures stabilized by hydrogen bonds have thus been achieved. − In contrast, self-assembled halogen-bonded 2D organic structures have only been recently investigated. − …”

Toward Two-Dimensional Tessellation through Halogen Bonding between Molecules and On-Surface-Synthesized Covalent Multimers

“…Atomic-scale engineering of sophisticated two-dimensional (2D) organic nanoarchitectures composed of various building blocks is attracting increasing research interest [1][2][3][4]. This can be achieved by depositing differently shaped molecular building blocks on surfaces and taking advantage of molecular self-assembly through directive and selective intermolecular interactions, such as hydrogen [5][6][7] and halogen bonds [8][9][10][11][12][13][14]. Numerous multicomponent 2D nanoarchitectures have been achieved by taking advantage of hydrogen bonds [15][16][17][18][19][20], but multicomponent 2D nanoarchitectures stabilized by halogen bonds are more scarce.…”