Unusual In-plane Aromaticity Facilitates Intramolecular Hydrogen Transfer in Long-Bonded cis-Isonitrosyl Methoxide,The Journal of Physical Chemistry A

当前位置： X-MOL 学术 › J. Phys. Chem. A › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Unusual In-plane Aromaticity Facilitates Intramolecular Hydrogen Transfer in Long-Bonded cis-Isonitrosyl Methoxide
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2022-09-01 , DOI: 10.1021/acs.jpca.2c03315
Punhasa S Senanayake ₁ , Raulia R Syrlybaeva ₁ , Marat R Talipov ₁

Affiliation

The hydrogen-atom transfer from methoxy radical to nitric oxide, leading to the formation of formaldehyde and nitroxyl, represents a secondary reaction of photodissociation of methyl nitrite, which is used as rocket fuel. In this study, we explored the potential energy profile of the hydrogen-atom transfer using the electronic structure calculations at the DLPNO-CCSD(T)/aug-cc-pVTZ level of theory for two isomeric forms (cis and trans) of the pre-reaction complex. The cis-oriented pre-reaction complex has a weak elongated O─O bond, which gets further elongated in the hydrogen transfer transition state. This O─O bond stabilizes the pre-reaction complex by 32.9 kJ/mol. The O─O-induced stabilization is even greater for the transition state (48.2 kJ/mol), which was unexpected because of the larger O─O distance in the transition state structure. To address this paradox, we performed the electronic structure analysis of the reaction participants using the valence bond (VB) theory, natural resonance theory, topological analysis of the electron density and its derivatives, and analysis of the electron localization function distribution. This combined analysis led to the conclusion that the cis-transition state for hydrogen transfer, instead of being directly stabilized by the O─O interaction, gained substantial stabilization from the in-plane five-center six-electron aromaticity.

中文翻译：

不寻常的面内芳香性促进长键顺式-异亚硝基甲醇盐中的分子内氢转移

氢原子从甲氧基自由基转移到一氧化氮，导致甲醛和硝酰基的形成，代表了用作火箭燃料的亚硝酸甲酯光解的二次反应。在这项研究中，我们使用 DLPNO-CCSD(T)/aug-cc-pVTZ 理论水平的电子结构计算，探索了氢原子转移的势能分布，用于两种异构形式（顺式和反式）的预-反应复合体。顺式取向的预反应配合物具有弱伸长的O─O键，在氢转移过渡态进一步伸长。这个 O─O 键使预反应复合物稳定了 32.9 kJ/mol。对于过渡态（48.2 kJ/mol），O─O 诱导的稳定性甚至更大，这是出乎意料的，因为过渡态结构中的 O─O 距离较大。为了解决这个悖论，我们使用价键（VB）理论、自然共振理论、电子密度及其衍生物的拓扑分析以及电子定位函数分布分析对反应参与者进行了电子结构分析。这种综合分析得出的结论是，顺式氢转移的过渡态不是直接通过O─O相互作用稳定，而是从面内五中心六电子芳香性中获得了实质性的稳定。

更新日期：2022-09-01

点击分享查看原文

点击收藏

阅读更多本刊新发论文