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

“…Recent research 52 has led to the successful synthesis of a new and innovative compound known as heterotriangulene, which is formed by assembling triangulene with boron, carbon, and oxygen. This breakthrough has prompted us to investigate the possibility of stable 2D materials consisting solely of these three elements but with covalent bonds.…”

“…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.…”

Magnetic Coupling Control in Triangulene Dimers

“…Triangulene has been proposed as a prototype for studying other PAHs, which can be doped, substituted, or incorporated into more complex architectures. ,− Recent developments in the synthesis of extended structures made of triangulenes have led to the observation of many exotic phenomena, such as Dirac cones, collective spin excitation, ,, and Haldane phase . Despite the successful realization of triangulene monomers, dimers, nanostars, quantum rings, and 1D polymers, as well as its larger homologues such as [4]-, [5]-, and [6]-triangulene, ,− the chemical versatility of triangulene and its derivatives remains understudied, especially for those with heteroatoms. ,− For hydrocarbons with a bipartite honeycomb lattice, the well-established Ovchinnikov rule, i.e. Lieb’s theorem, is commonly applied to predict the spin-polarized ground states of the non-Kekulé molecules.…”