Coronene guest molecule selectivity in host templates formed by hydrogen bonding and van der Waals forces at liquid/solid interfaces

Abstract

Hydrogen bonding and van der Waals forces are important non-covalent interactions for constructing supramolecular self-assembly networks. The directivity of hydrogen bonding brings about rich and diverse structures and properties for hydrogen-bonded organic frameworks (HOFs), and has been an ongoing interest for researchers. However, there are few studies on the selective adsorption of the same guest molecule in a host template constructed by different intermolecular interactions. In this work, the self-assembly behaviors of two carboxylic acid molecules, namely 1,3,5-tris(4-(3,5-dicarboxyphenyl)diphenyl)benzene (H₆PDB) and 1,3,5-tris(4-(3,5-dicarboxyphenylacetylene)phenyl)benzene (H₆PAB), were studied by scanning tunneling microscopy (STM). The molecules self-assembled into structures with two kinds of cavities, where the hexagonal cavities demonstrated different behaviors when accommodating guest coronene (COR) molecules. In H₆PAB and hexaphenylbenzene derivative (HPB) templates, the COR guest molecules preferentially adsorbed in the H₆PAB host templates, showing selective adsorption.