Insight into The Nature of Rim Bonds in Coronene
Insight into The Nature of Rim Bonds in Coronene
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DOI：
10.1021/acs.jpca.8b07937
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发表时间：
2018-11-01
影响因子：
2.9
通讯作者：
Boldyrev, Alexander I.
中科院分区：
文献类型：
--
作者：
Fedik, Nikita;Boldyrev, Alexander I.
在化学上，晕苯被称为芳香族或甚至超芳香族分子，但它有24个π电子，不符合4 n + 2休克尔规则。化学中对它的化学键描述还没有固定下来，文献中报道了五种模型。根据我们的模型，晕苯有两个同心π系统负责分子内部的芳香性。除此之外，还有六个外围2c-2 e π键，这使得晕苯同时具有脂肪族/芳香族。然而，最近的实验和计算对外围π键的存在提出了质疑。为了解决这个问题，我们计算研究了Cl-2分子与C2 H4，C6 H6和C24 H12的反应机理。事实证明，通过加入Cl-2分子，晕苯的行为类似于乙烯。从而证明了晕苯确实具有外围双键，这也与晕苯的实验几何特征相一致。我们的化学键合模型可以识别晕苯和其他多环芳烃中最具反应性的原子，因此，它是燃烧和烟尘形成研究的重要问题。
Coronene is known in chemistry as an aromatic or even superaromatic molecule while it has 24 pi-electrons which does not conform to the 4n + 2 Huckel's rule. Chemical bonding description of it is not settled in chemistry and five models were reported in the literature. According to our model, coronene has two concentric pi-systems responsible for aromaticity inside of the molecule. In addition to that there are six peripheral 2c-2e pi-bonds, which makes coronene aliphatic/aromatic at the same time. However, recent experiments and calculations put in question the presence of peripheral pi-bonds. In order to resolve this issue, we computationally studied reaction mechanism of the Cl-2 molecule with C2H4, C6H6, and C24H12. As it turned out, coronene behaves in a way similar to ethylene by adding Cl-2 molecule. Thus, it proves that coronene indeed has peripheral double bonds which is also consistent with its experimental geometrical features. Our chemical bonding model allows to identify the most reactive atoms in coronene and other PAHs; therefore, it is a matter of importance for combustion and soot formation studies.