Heteroatom‐Edged [4]Triangulene: Facile Synthesis and Two‐Dimensional On‐Surface Self‐Assemblies**

Abstract

Triangulenes have attracted enormous interest in organic chemistry and materials science, but suffer from their high instability towards oxygen. Embedding heteroatoms into triangulenes provides a new class of ambient stable materials for various applications. However, [3]heterotriangulenes have dominated the chemistry of heteroatom‐doped triangulenes, while their higher homologues have been rarely explored. In this work, we synthesize a new [4]heterotriangulene with three oxygen‐boron‐oxygen (OBO) segments incorporated into the zigzag edges. The planar geometry of the OBO‐doped [4]triangulene is demonstrated by single‐crystal X‐ray diffraction. Self‐assembly on metal surfaces reveals substrate‐dependent nanostructures, leading to different long‐range ordered 2D patterns on Ag and Cu substrates with negligible defects.

New two-dimensional flat band materials: B3C11O6 and B3C15O6

“…Recently, Cheng Chen et al incorporated oxygen-boron-oxygen (OBO) segments into triangulenes to enhance their stability. 71 The two monolayers we propose can be split into OBO segments and either carbon clusters or a carbon skeleton. This suggests that the two monolayers can be synthesized through a similar experimental process.…”

Electronic Structure Modulation of Nanographenes for Second Order Nonlinear Optical Molecular Materials

“…The BNB‐doped polycyclic aromatic hydrocarbons show blue fluorescence [29b,30a,b] . OBO‐doped NGs exhibit excellent stability under acidic and oxidative conditions and strong fluorescence with respect to that of its all‐carbon analogues, [26a] display a rare anti‐Kasha fluorescence and phosphorescence emissions from higher excited states, [26b] and present good air stability as well as ordered self‐assembled behavior [26c] . Modification of hexagon or azulene moieties by heteroatoms confer these molecules with tunable properties, for instance, the azulene‐pyridine‐fused heteroaromatics display strong aromaticity with rigid planar π‐structures and p‐type semiconducting behavior with a high hole mobility [21,66] .…”

Heteroatom-boron-heteroatom-doped π-conjugated systems: structures, synthesis and photofunctional properties

“…5, the [4]triangulenes bounded by three O-B-O units have been independently reported by both our research team and Wang's group. 39,40 The synthesis of OBO- [4]triangulenes was achieved through a sequence involving a sixfold Lewis acidmediated demethylation, succeeded by a threefold electrophilic borylation reaction. In this process, the base 2,2,6,6-tetramethylpiperidine (TMP) played a pivotal role in enhancing the yield of the triple borylation step (Fig.…”