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

作者：Wang, Yi; Zou, Hengqi; Liu, Yuanjiao; Miao, Xinrui^*; Deng, Wenli^*; Yuan, Qunhui^*

来源：Langmuir : the ACS journal of surfaces and colloids , 2023, 39(23): 8314-8322.

DOI：10.1021/acs.langmuir.3c00866

• LIQUID/SOLID INTERFACE
• HALOGEN BOND
• ADSORPTION
• MICROSCOPY
• DYNAMICS
• POSITION
• NETWORK
• CHARGE

Halogenbonding (XB) is of great importance in fabricatinga two-dimensional(2D) self-assembly for its adaptive directionality. However, the XBsinvolving fluorine (F) have barely been studied due to the absenceof an sigma-hole on F. Here, 2D self-assemblies of a F-substituted4,7-bis(5-bromo-4-dodecyl-thiophen-2-yl)-5,6-difluoro-benzo-[c][1,2,5]-thiadiazole(BTZ-BrF) molecule on graphite were investigated using scanning tunnelingmicroscopy (STM) and density functional theory (DFT) calculations.STM experiments revealed that the 2D patterns of BTZ-BrF had a clearsolvent and concentration dependence, showing a frame-like patternin aliphatic acid and aliphatic hydrocarbon solvents at high concentrations.At lower concentrations, a bamboo-like and a wave-like pattern wereobserved in aliphatic acid, whereas small frame-like and large ladder-likedomains at high solution concentrations in aliphatic hydrocarbon wereobserved. As the concentration further decreased, two linear patternswere observed. DFT calculations suggested that the hetero-XBs of F center dot center dot center dot Br,F center dot center dot center dot S, Br center dot center dot center dot S, and Br center dot center dot center dot N,the homo-XBs of type-II Br center dot center dot center dot Br, and the S center dot center dot center dot Sinteractions synergistically directed and stabilized the polymorphic2D architectures. This understanding of intermolecular XBs duringthe molecular assembly at the molecular level may shed light on theongoing efforts of regulating nanostructures of multifunctional organics.