Studies on the bent thoracene with low coordinated bridging units using density functional theory

IF 3 3区化学 Q3 CHEMISTRY, PHYSICAL

Computational and Theoretical Chemistry Pub Date : 2025-05-21 DOI:10.1016/j.comptc.2025.115295

Sarita Yadav, Pooja, Ravinder Pawar

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引用次数: 0

Abstract

Metallocenophanes are well established as the most prominent organometallic analogs of cyclophanes. In contrast, the intriguing domain of actinocenophanes remains largely unexplored. Hence, density functional theory (DFT) calculations are employed in the present study to investigate a series of [3]thoracenophanes incorporating X-Y-X ansa moieties. These moieties feature a low-coordinated center Y (comprising C, Si, or Ge), stabilized by adjacent donor units X (NMe, O, or S). These ansa-bridged [3]thoracenophanes predominantly feature cyclooctatetraene dianion (COT²⁻) in an eclipsed configuration. Notably, a tilting of the COT²⁻rings is observed when thoracene is bridged with second-row elements, in contrast to the third-row elements. Analysis of the singlet-triplet gap (

∆ E_{s - t}

) reveals that the triplet states of all investigated carbenes possess higher energy than the corresponding singlet states. Frontier molecular orbital (FMO) analysis further demonstrates that the identity of the heteroatom (X) in the ansa moiety plays a crucial role in stabilizing the low-coordinated carbon (C) of the thoracenophane complex. Furthermore, natural bond orbital (NBO) analysis was conducted to comprehend the stabilization of the resulting carbene-based thoracenophane complexes. The results reveal that, intriguingly, no direct orbital interaction occurs between the thorium center and the ansa bridge, highlighting the primary role of the carbene-based low-coordinated ansa unit in altering the properties through geometrical modifications. This study opens a new avenue for exploring the reactivity patterns of these [3]thoracenophanes toward small-molecule activation and for extending the ansa-bridge design to other actinides for advanced catalytic applications.

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基于密度泛函理论的低协调桥单位弯曲胸的研究

金属茂烯醚已被公认为是环烷最突出的有机金属类似物。相比之下，令人感兴趣的放线菌素领域大部分仍未被探索。因此，本研究采用密度泛函理论（DFT）计算来研究一系列含有X-Y-X ansa基团的[3]胸内芬。这些基团具有低配位的中心Y（包括C、Si或Ge），由相邻的供体单位X （NMe、O或S）稳定。这些ansa桥接的[3]胸烯醚主要以重叠构型的环四烯离子（COT2−）为特征。值得注意的是，与第三行元件相比，当胸烯与第二行元件桥接时，可以观察到COT2−环的倾斜。单重态-三重态间隙（∆Es−t）的分析表明，所研究的所有碳烯的三重态都比相应的单重态具有更高的能量。前沿分子轨道（FMO）分析进一步表明，杂原子(X)在ansa片段中的身份对稳定胸烯酚配合物的低配位碳(C)起着至关重要的作用。此外，通过自然键轨道（NBO）分析了解了羰基胸萘芬配合物的稳定性。结果显示，有趣的是，钍中心和ansa桥之间没有直接的轨道相互作用，突出了碳基低配位ansa单元通过几何修饰改变性质的主要作用。本研究为探索这些[3]胸酚类化合物的小分子活化活性模式，以及将ansa-bridge设计扩展到其他锕系元素的高级催化应用开辟了新的途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Computational and Theoretical Chemistry CHEMISTRY, PHYSICAL-

CiteScore

4.20

自引率

10.70%

发文量

331

审稿时长

31 days

期刊介绍： Computational and Theoretical Chemistry publishes high quality, original reports of significance in computational and theoretical chemistry including those that deal with problems of structure, properties, energetics, weak interactions, reaction mechanisms, catalysis, and reaction rates involving atoms, molecules, clusters, surfaces, and bulk matter.