Azadihomocorannulene as a Heptagon-Embedded Diradicaloid
Yosuke Hamamoto1, Weifan Wang1, Yongxin Li1
1School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore, Singapore.
Abstract:
Polycyclic aromatic diradical(oid) molecules are attracting significant attention because of their unique electronic and magnetic properties as well as their applications as functional materials. While diradical(oid) molecules bearing five-membered rings have been extensively investigated, those bearing seven-membered rings are relatively fewer. Herein, we report the synthesis of azapentabenzodihomocorannulene dication and diradical molecules. The synthesis was achieved through a mechanochemical C(sp2)-H/C(sp3)-H coupling in the presence of sodium as a key reaction. Electron spin resonance studies revealed that the neutral azapentabenzodihomocorannulene adopts a singlet diradical (diradicaloid) ground state with a small singlet-triplet energy gap of 2.1 kcal/mol. The electronic and optical properties were investigated both experimentally and theoretically to elucidate their aromatic character.
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