title: Toward Stable Superbenzoquinone Diradicaloids.
abstract: Superbenzoquinone (SBQ) is a quinone derived from a classic polycyclic aromatic hydrocarbon (PAH), hexa-peri-hexabenzocoronene (so-called "superbenzene"), and is a challenging synthetic target. Herein we report the successful synthesis and characterization of its derivatives. We reveal that the high reactivity of SBQ is due to its intrinsic open-shell diradical character. Thus, two kinetically blocked SBQs, SBQ-Me and SBQ-Ph, were prepared by different synthetic strategies. 4-tert-Butylphenyl-substituted SBQ-Ph demonstrated good stability and could be isolated in crystalline form. Both compounds have an open-shell singlet ground state and show thermally populated paramagnetic activity. Our studies provide effective strategies toward stable quinone-based diradicaloids.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
authors.forename: Guangwu
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
authors.forename: Hoa
authors.initials: H
authors.lastname: Phan
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore, Singapore.
authors.forename: Tun Seng
authors.initials: TS
authors.lastname: Herng
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
authors.forename: Tullimilli Y
authors.initials: TY
authors.lastname: Gopalakrishna
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
authors.forename: Chunchen
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
authors.forename: Wangdong
authors.initials: W
authors.lastname: Zeng
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore, Singapore.
authors.forename: Jun
authors.initials: J
authors.lastname: Ding
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
authors.forename: Jishan
authors.initials: J
authors.lastname: Wu
keywords: diradicaloids; dyes/pigments; near-infrared dyes; polycyclic aromatic hydrocarbons; quinones