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 (B2N2‐ixene), and their characterizations. Compared to ixene, B2N2‐ixene absorbs longer‐wavelength light and has a smaller electrochemical energy gap. In addition to its single‐crystal structure, scanning tunneling microscopy revealed that B2N2‐ixene adopts a nonplanar geometry on a Au(111) surface. The experimentally obtained electronic structure of B2N2‐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. A forgotten curiosity: Ixene, a compound that was previously named but never prepared, and its BN‐doped derivative (B2N2‐ixene) were synthesized in two steps from simple intermediates. The effect of BN‐doping, or substitution of carbon–carbon bonds with isoelectronic boron–nitrogen bonds, was elucidated both experimentally and theoretically.