Research Projects

Antiaromaticity is a crucial property of planar π-conjugated molecules with 4nπ-electrons in a cyclic conjugation. It is important in biological research and materials science, as it can help answer the intrinsic instability of DNA caused by antiaromaticity. Recent studies have demonstrated excellent hole mobilities of up to 6.55 cm2/V/s. s-Indacene and as-indacene are isomeric 12πe antiaromatic polycyclic hydrocarbons. Most research has focused on s-indacene-based π-systems, but a major research gap lies in exploring a heterocyclic quinodimethane motif with a heteroatom-modified as-indacene unit. The proposed benzannulation approach aims to stabilize closed-shell and open-shell ground states for sulfur and selenium modified heterocyclic as-indacene scaffolds. The molecules will be synthesized and characterized using x-ray crystallographic analysis and DFT calculations. Modulation of antiaromaticity of s-indacene-based π-systems has received attention for its fundamental understanding of (anti)aromaticity, amphoteric redox behavior, open-shell character, unique optoelectronic properties, and ambipolar charge carrier mobility. The synthesis of heteropin-annulated as-indacene scaffolds 8 includes azepine (8-NMe), oxepine (8-O), thiepine (8-S), and selenepine (8-Se). Heteropin is a seven-membered heterocycle analogue of cyclooctatetraene, with little known about it from a physical organic chemistry viewpoint. The design of these new scaffolds is based on DFT calculations, with oxepine-annulated as-indacene predicted to show a greater degree of antiaromaticity due to its planar structure, strong electronegativity of an oxygen atom, and photoexcitation pattern.