Technische Universität Berlin, Institut für Chemie, Theoretische Chemie, Sekr, C7, Straße des 17, Juni 135, 10623 Berlin, Germany.
Phys Chem Chem Phys. 2011 Oct 14;13(38):16973-86. doi: 10.1039/c1cp21772k. Epub 2011 Aug 31.
This article discusses recent progress by a combination of spectroscopy and quantum-chemical calculations in classifying and characterizing organic mixed-valence systems in terms of their localized vs. delocalized character. A recently developed quantum-chemical protocol based on non-standard hybrid functionals and continuum solvent models is evaluated for an extended set of mixed-valence bis-triarylamine radical cations, augmented by unsymmetrical neutral triarylamine-perchlorotriphenylmethyl radicals. It turns out that the protocol is able to provide a successful assignment to class II or class III Robin-Day behavior and gives quite accurate ground- and excited-state properties for the radical cations. The limits of the protocol are probed by the anthracene-bridged system 8, where it is suspected that specific solute-solvent interactions are important and not covered by the continuum solvent model. Intervalence charge-transfer excitation energies for the neutral unsymmetrical radicals are systematically overestimated, but dipole moments and a number of other properties are obtained accurately by the protocol.
本文通过光谱学和量子化学计算的结合，讨论了在有机混合价系统中对局部和离域特征进行分类和描述的最新进展。评估了一种新开发的基于非标准杂化泛函和连续溶剂模型的量子化学方案，该方案扩展到了一系列混合价双三芳基胺自由基阳离子，其中还增加了不对称中性三芳基胺-高氯酸三苯甲基自由基。结果表明，该方案能够成功地对类 II 或类 III Robin-Day 行为进行分配，并为自由基阳离子提供了相当准确的基态和激发态性质。通过蒽桥接体系 8 探测了该方案的局限性，在该体系中，怀疑特定的溶质-溶剂相互作用很重要，并且不能用连续溶剂模型来覆盖。对于中性不对称自由基的价间电荷转移激发能，该方案被系统地高估，但偶极矩和许多其他性质都被该方案准确地获得。
