Synthesis and Properties of Azahomocorannulenyl Cations and Radicals

Angew Chem Int Ed Engl. 2024 Feb 12;63(7):e202319022. doi: 10.1002/anie.202319022. Epub 2024 Jan 12.

Abstract

Cycloheptatrienyl (tropyl) molecules are representative non-alternant hydrocarbons that offer interesting chemistry because of their unique structures and properties. However, there have been a limited number of polycyclic aromatic tropyl cations and radicals reported in the literature. Herein, we report the synthesis of a series of azahomocorannulene derivatives, where the key reactions are a 1,3-dipolar cycloaddition of polycyclic aromatic azomethine ylides with dibenzotropone and a subsequent palladium-catalyzed cyclization. X-ray diffraction analysis revealed that the obtained azahomocorannulenyl cation and radical adopt planar structures and exhibit unique packing structures. Their electronic and optical properties were investigated experimentally and theoretically to reveal their aromatic character.

Keywords: 1,3-Dipolar Cycloaddition; Azahomocorannulene; Polycyclic Aromatic Molecules; Tropyl Radicals; Tropylium.