Unveiling 79-Year-Old Ixene and Its BN-Doped Derivative

Polycyclic aromatic hydrocarbons (PAHs) are key components of organic electronics. The electronic properties of these carbon-rich materials can be controlled through doping with heteroatoms such as B and N, however, few convenient syntheses of BN-doped PAHs have been reported. Described herein is the rationally designed, two-step syntheses of previously unknown ixene and BN-doped ixene (B₂ N₂ -ixene), and their characterizations. Compared to ixene, B₂ N₂ -ixene absorbs longer-wavelength light and has a smaller electrochemical energy gap. In addition to its single-crystal structure, scanning tunneling microscopy revealed that B₂ N₂ -ixene adopts a nonplanar geometry on a Au(111) surface. The experimentally obtained electronic structure of B₂ N₂ -ixene and the effect of BN-doping were confirmed by DFT calculations. This synthesis enables the efficient and convenient construction of BN-doped systems with extended π-conjugation that can be used in versatile organic electronics applications.