Kiulene

Kiulene is a polycyclic aromatic hydrocarbon (PAH) characterized by a non-planar, bowl-shaped geometry arising from the fusion of multiple benzene rings. It is part of a family of curved PAHs that includes corannulene and kekulene, molecules studied for their distorted π-systems and potential uses in molecular electronics and host–guest chemistry.

Structure and properties: Kiulene consists of fused aromatic rings arranged to produce curvature out of the plane. The curvature influences how electronic charge is distributed across the molecule and can affect aromaticity, optical absorption, and redox behavior. The framework is highly conjugated, often yielding broad absorption in the visible region and potential semiconducting or redox-active characteristics. Functionalization with alkyl or aryl groups is commonly explored to improve solubility and processability for characterization and applications.

Synthesis and characterization: Approaches to kiulene-like structures generally rely on multi-step organic syntheses that build up the fused-ring backbone through annulation and cyclization of smaller precursors, followed by dehydrogenation to achieve a fully aromatic system. Characterization typically uses nuclear magnetic resonance spectroscopy, mass spectrometry, UV–visible spectroscopy, and X-ray crystallography or advanced scanning probe techniques to confirm curvature and topology.

Applications and significance: As a curved PAH, kiulene serves as a model system for studying how molecular geometry influences electronic structure and intermolecular interactions. Potential applications include roles in nanoelectronics, sensing, and the construction of supramolecular assemblies that exploit defined cavities and curvature to host guest species.

See also: Corannulene, Kekulene, Curved PAHs, Polycyclic aromatic hydrocarbons.