Controlled Construction of an Exquisite Three-Component Co-assembly Supramolecular Structure at the Liquid-Solid Interface.

A three-component supramolecular co-assembly structure formed at the liquid-solid interface by employing a shape-persistent π-conjugated macrocycle (1) and two guest molecules (COR and C) is demonstrated. Scanning tunneling microscopy (STM) observations revealed that 1 can serve as a versatile host molecule that can co-assemble with both COR and C guest molecules to form stable two-component structures, where the COR guest molecule filled in the gap between the side chains of adjacent 1 molecules, and the C guest molecule entered the inner cavity of 1. It was found that the adding sequence of COR and C guest molecules is crucial to the resulting co-adsorption structure in the three-component system. To obtain the intriguing 1-COR-C three-component co-assembly structure, the 1 and COR two-component co-assembly structure should first be constructed on a HOPG surface, followed by addition of C. Based on the analysis of the STM results and the density functional theory (DFT) calculations, the formation mechanism of the assembled structures was revealed.