Temperature induced supramolecular structural transition and as a host cavity to capture the guest molecules

The two-dimensional (2D) molecular self-assembled arrangements at the liquid?solid interface are dominated by many parameters such as the molecular structure and the environment of adsorbed molecules. In this study, the impact of temperature on the self-assembled structures of tetrathiafulvalene derivatives TTF-C6, which contains two aromatic carboxyl groups and two alkyl side chains, was investigated by scanning tunneling microscopy (STM) technique. Experimental result reveals that the compacted linear structures of TTF-C6 can be transformed into the cavity structures by increasing the HOPG substrate temperature. The cavity structures can serve as template system to capture different guest molecules such as coronene (COR) and C60. However, the proportion of two guest molecules in the host cavities is different. The corresponding density functional theory (DFT) calculations were carried out to verify the experimental results. Such temperature-induced structural transitions are used to adjust the packing density of molecule and capture different guest molecule.