Mou Zhongyu, Kubo Takashi, Kertesz Miklos
Department of Chemistry, Georgetown University, Washington, DC 20057 (USA).
Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan).
Chemistry. 2015 Dec 7;21(50):18230-6. doi: 10.1002/chem.201503409. Epub 2015 Nov 5.
Homogeneous π-stacking dimers of phenalenyl and its derivatives have gained tremendous interest as components of conducting organic materials. For the first time, we investigate theoretically heterogeneous phenalenyl π-dimers. Key parameters, including charge transfer, interaction energy, singly occupied molecular orbital (SOMO) energy, and spin density, are studied with the help of density functional theory. We find that the amount of charge transfer between the two monomers in phenalenyl π-dimers correlates with the difference in the SOMO energies of the constituent monomers, where the SOMO energy plays the role of a monomer (group) electronegativity index. Charge transfer plays an important role in stabilizing the heterodimers while maintaining a significant diradicaloid character. For five heterodimers the interaction energy is found to be as large as -30 to -50 kcal mol(-1) . The presented correlation between the monomer SOMO energy levels and their stability can provide a simple predictive tool to design new highly stable π-stacking heterodimers.
苊烯及其衍生物的均相π堆积二聚体作为导电有机材料的组成部分引起了极大的关注。我们首次对非均相苊烯π二聚体进行了理论研究。借助密度泛函理论研究了包括电荷转移、相互作用能、单占据分子轨道（SOMO）能量和自旋密度在内的关键参数。我们发现，苊烯π二聚体中两个单体之间的电荷转移量与组成单体的SOMO能量差异相关，其中SOMO能量起着单体（基团）电负性指数的作用。电荷转移在稳定异二聚体的同时保持显著的双自由基特征方面起着重要作用。对于五个异二聚体，发现相互作用能高达-30至-50 kcal mol(-1) 。所呈现的单体SOMO能级与其稳定性之间的相关性可为设计新型高稳定性π堆积异二聚体提供一个简单的预测工具。
