Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore, Singapore.
Angew Chem Int Ed Engl. 2017 Apr 24;56(18):5012-5016. doi: 10.1002/anie.201700441. Epub 2017 Mar 30.
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.
超苯醌（SBQ）是一种醌类化合物，来源于经典的多环芳烃（PAH）六并苯[1,2-b:5,6-b']二呋喃（所谓的“超级苯”），是一个具有挑战性的合成目标。本文报道了其衍生物的成功合成和表征。我们揭示了 SBQ 的高反应性源于其固有的开壳双自由基特性。因此，通过不同的合成策略制备了两种动力学受阻的 SBQ-Me 和 SBQ-Ph。用 4-叔丁基苯基取代的 SBQ-Ph 表现出良好的稳定性，可以结晶形式分离。这两种化合物均具有开壳单线态基态，显示出热激发的顺磁活性。我们的研究为稳定的基于醌的双自由基提供了有效的策略。
