Weak and strong π interactions between two monomers—assessed with local vibrational mode theory
Weak and strong π interactions between two monomers—assessed with local vibrational mode theory
复制标题
两个单体之间的弱和强α相互作用——用局部振动模式理论进行评估
DOI：
10.1139/cjc-2022-0254
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发表时间：
2023
影响因子：
1.1
通讯作者：
Kraka, Elfi
中科院分区：
文献类型：
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作者：
Zou, Wenli;Freindorf, Marek;Oliveira, Vytor;Tao, Yunwen;Kraka, Elfi
我们在这项工作中引入了一个独特的参数，用于定量评估形成络合物的两个单体之间π相互作用的内在强度。新的参数是基于局部模态理论的单体间局部拉伸力常数，该理论最初由Konkoli和Cremer提出，并从9种可能的单体间正振型中导出。新的局部力常数被应用于70多个不同的分子复合物，它们被分为四组。第1族包括与苯和取代苯相互作用的原子、离子和小分子。第2族包括与苯相互作用的过渡金属氢化物和氧化物，而第3族包括二茂铁、二茂铬和钛夹层化合物。与面内氢键相比，族4表现出氧π -空穴相互作用的扩展。我们发现π相互作用的强度在这些不同的分子配合物中可以从弱相互作用（主要是静电作用，如氩-苯配合物）到强相互作用（如二茂铁）；所有这些都被无缝地描述并与新的单体间局域模式力常数进行了比较，后者也优于其他描述符，如平均力常数或由电子密度键路径引导的力常数。我们希望我们的研究结果将激励社区将新参数也应用于其他单体间π相互作用，以这种方式丰富有机金属化学的广泛领域，并提供一种新的有效评估工具。
We introduce in this work a unique parameter for the quantitative assessment of the intrinsic strength of the π interaction between two monomers forming a complex. The new parameter is a local intermonomer stretching force constant, based on the local mode theory, originally developed by Konkoli and Cremer, and derived from the set of nine possible intermonomer normal vibrational modes. The new local force constant was applied to a diverse set of more than 70 molecular complexes, which was divided into four groups. Group 1 includes atoms, ions, and small molecules interacting with benzene and substituted benzenes. Group 2 includes transition metal hydrides and oxides interacting with benzene while Group 3 involves ferrocenes, chromocenes, and titanium sandwich compounds. Group 4 presents an extension to oxygen π–hole interactions in comparison with in-plane hydrogen bonding. We found that the strength of the π interactions in these diverse molecular complexes can vary from weak interactions with predominantly electrostatic character, found, eg, for argon–benzene complexes, to strong interactions with a substantial covalent nature, found, eg, for ferrocenes; all being seamlessly described and compared with the new intermonomer local mode force constant, which also outperforms other descriptors such as an averaged force constant or a force constant guided by the electron density bond paths. We hope that our findings will inspire the community to apply the new parameter also to other intermonomer π interactions, enriching in this way the broad field of organometallic chemistry with a new efficient assessment tool.