Unveiling 79-year-old ixene and its BN-doped derivative

Abstract

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 pi-conjugation that can be used in versatile organic electronics applications.