Controlled Formation of Porous 2D Lattices from C3-symmetric Ph6-Me-Tribenzotriquinacene-OAc3

The on-surface self-assembly of molecules to form holey nanographenes is a promising approach to control the properties of the resulting 2D lattice. Usually, planar molecules are utilized to prepare flat, structurally confined molecular layers, with only a few recent examples of warped precursors. However, control of the superstructures is limited thus far. Herein, we report the temperature-controlled self-assembly of a bowl-shaped, acetylated C-3-symmetric hexaphenyltribenzotriquinacene derivative on Cu(111). Combining scanning tunneling microscopy (STM) and density functional theory (DFT) confirms the formation of highly differing arrangements starting with pi-stacked bowl-to-bowl dimers at low coverage at room temperature via chiral honeycomb structures, an intermediate trigonal superstructure, followed by a fully carbon-based, flattened hexagonal superstructure formed by on-surface deacetylation, which is proposed as a precursor for holey graphene networks with unique defect structures.

Automated summary

The on-surface self-assembly of a bowl-shaped derivative on Cu(111) is reported, showing highly different arrangements at different temperatures. The formation process includes pi-stacked bowl-to-bowl dimers, chiral honeycomb structures, an intermediate trigonal superstructure, and a fully carbon-based, flattened hexagonal superstructure. This provides a potential precursor for holey graphene networks with unique defect structures.