Su Bochao, Ota Kei, Xu Kai, Hirao Hajime, Kinjo Rei
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore.
Department of Chemistry , City University of Hong Kong , Tat Chee Avenue, Kowloon , Hong Kong , China.
J Am Chem Soc. 2018 Sep 26;140(38):11921-11925. doi: 10.1021/jacs.8b08025. Epub 2018 Sep 17.
Despite the large number of plausible isomers of benzene (CH), only four valence isomers [(CH)] have been experimentally detected, all of which are nonionic and possess skeletal frameworks built from localized C-C bonds. Herein, we present the isolation of a diazatetraborabenzene analogue of a hypothetical zwitterionic valence isomer of benzene. Therein, two electrons are delocalized over the four boron atoms in the six-membered BN ring, which is a result of the σ-bonding interaction between two odd-electron B-B π-orbitals. Simple treatment with a crown ether leads to the formation of a paramagnetic potassium-doped radical ion pair that exhibits a thermally populated triplet character.
尽管苯（CH）存在大量可能的异构体，但通过实验仅检测到四种价键异构体[（CH）]，它们均为非离子型，且具有由定域C-C键构成的骨架结构。在此，我们展示了一种苯的假设两性离子价键异构体的二氮杂四硼苯类似物的分离。其中，两个电子在六元BN环中的四个硼原子上离域，这是两个奇电子B-B π轨道之间σ键相互作用的结果。用冠醚进行简单处理会导致形成一种顺磁性钾掺杂自由基离子对，该离子对表现出热激发的三重态特征。
