Magnetic Exchange Interactions: Mechanistic Insights and Understanding Orbital Influences in Organic Diradicals

IF 4.8 3区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Journal of Computational Chemistry Pub Date : 2025-09-18 DOI:10.1002/jcc.70230

Chumuiria Debbarma, Debojit Bhattacharya, Suranjan Shil

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引用次数: 0

Abstract

Frontier molecular orbitals play a crucial role in determining the magnetic behavior and exchange interactions in organic radicals. In this study, we investigate the underlying mechanism influencing the need for orbital planarity and the role of frontier orbital overlap in magnetic exchange interactions. To study this, we designed a series of 12 polyacene-coupled triarylmethyl diradicals, systematically increasing in length of polyacene. We have used nine different DFT functionals for the calculation of the magnetic exchange coupling constant (J). The calculation of magnetic exchange coupling reveals that the GGA functionals define a more accurate spin state, hence more correct magnetic behavior than the meta-GGA and hybrid functionals. We have studied the effect of orbital orientation and their energy gap to understand the high magnetic exchange coupling in the higher polyacene-coupled diradicals. Our calculations revealed that the planarity and overlap of the frontier molecular orbitals are one of the key factors in influencing the strength and behavior of the magnetic exchange interactions in diradicals. Specifically, the overlap between SOMOs and LUMO influences the strength of the magnetic exchange interaction.

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磁交换相互作用：有机双基中轨道影响的机理和理解。

前沿分子轨道在确定有机自由基的磁性行为和交换相互作用方面起着至关重要的作用。在这项研究中，我们探讨了影响轨道平面性需求的潜在机制以及前沿轨道重叠在磁交换相互作用中的作用。为了研究这一点，我们设计了一系列12个聚苯二烯偶联的三芳基甲基二自由基，系统地增加了聚苯二烯的长度。我们使用了9种不同的DFT泛函来计算磁交换耦合常数(J)。磁交换耦合计算表明，GGA泛函定义了更精确的自旋态，因此比元GGA和杂化泛函更正确的磁行为。我们研究了轨道取向及其能隙的影响，以理解高聚二烯偶联双自由基的高磁交换耦合。我们的计算表明，前沿分子轨道的平面度和重叠度是影响双基中磁交换相互作用强度和行为的关键因素之一。具体来说，somo和LUMO之间的重叠影响了磁交换相互作用的强度。

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

Journal of Computational Chemistry 化学-化学综合

CiteScore

6.60

自引率

3.30%

发文量

247

审稿时长

1.7 months

期刊介绍： This distinguished journal publishes articles concerned with all aspects of computational chemistry: analytical, biological, inorganic, organic, physical, and materials. The Journal of Computational Chemistry presents original research, contemporary developments in theory and methodology, and state-of-the-art applications. Computational areas that are featured in the journal include ab initio and semiempirical quantum mechanics, density functional theory, molecular mechanics, molecular dynamics, statistical mechanics, cheminformatics, biomolecular structure prediction, molecular design, and bioinformatics.