Biradicaloid Behavior of a Twisted Double Bond
Biradicaloid Behavior of a Twisted Double Bond
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DOI：
10.1021/acs.jpclett.1c00664
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发表时间：
2021-05-13
影响因子：
5.7
通讯作者：
Kubo, Takashi
中科院分区：
文献类型：
--
作者：
Hamamoto, Yosuke;Hirao, Yasukazu;Kubo, Takashi
一个化合物具有高度扭曲的C=C键在中间键解离区域被分离，其biradicaloid性质的实验证明。合成了一种长链烷氧基取代的双蒽酮衍生物，通过引入的烷氧基链之间的疏水相互作用，将其扭曲构象组装成晶体. X射线晶体学分析表明，连接两个蒽酮环的C=C键具有较长的键长（1.429埃）和较大的扭转角（57.33度）。此外，ESR研究表明，扭曲的双蒽酮具有双自由基性质，具有23.8 kJ mol（-1）的小单重态-三重态能隙。在ESR谱中观察到的热激发三重态物种作为不同的精细结构沿着与Δ M-s = +/- 2禁戒跃迁。
A compound with a highly twisted C=C bond in the intermediate bond dissociation region was isolated, and its biradicaloid nature was experimentally demonstrated. A bianthrone derivative substituted with long-chain alkoxy groups was synthesized, and its twisted conformer was assembled into crystals through hydrophobic intermolecular interactions of the introduced alkoxy chains. X-ray crystallography revealed that the C=C bond connecting the two anthrone rings has a long bond length (1.429 angstrom) and a large torsional angle (57.33 degrees). In addition, ESR studies revealed that the twisted bianthrone has biradicaloid character with a small singlet-triplet energy gap of 23.8 kJ mol(-1). The thermally excited triplet species were observed in the ESR spectrum as distinct fine structures along with a Delta M-s = +/- 2 forbidden transition.