Modeling of charge-transfer transitions and excited states in d6 transition metal complexes by DFT techniques
Modeling of charge-transfer transitions and excited states in d6 transition metal complexes by DFT techniques
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DOI：
10.1016/j.ccr.2006.05.021
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发表时间：
2007-02
影响因子：
20.6
通讯作者：
A. Vlček;A. Vlček;S. Záliš
中科院分区：
文献类型：
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作者：
A. Vlček;A. Vlček;S. Záliš
介绍和讨论了（大部分）d 6过渡金属配合物的电荷转移电子激发态的密度泛函描述的最新进展。一个简短的理论背景的地方DFT之间的量子化学技术，并讨论了所涉及的近似。介绍了含时DFT（TD-DFT）对电子跃迁的处理，重点讨论了长程电荷分离所带来的挑战。讨论了如何用化学相关术语表征激发态的各种方法。几个详细的案例研究演示了如何DFT描述的电荷转移激发态的ReI或Ru II羰基二亚胺配合物，并解释他们的光物理和光化学。本“教程”部分之后是DFT和TD-DFT应用的电子光谱和激发态的性质的金属羰基化合物，强发射有机金属化合物，钌光敏剂，发光“光开关”和异腈配合物的铼和钌的概述。强调的计算过程中的结果的质量和获得的信息的类型的影响。因此，最准确的电荷转移跃迁能和描述的低价d 6金属配合物的激发态时，使用杂化泛函和计算的分子在实际溶剂中获得。这些配合物的电荷转移态的一个相当离域的图片出现，从而电子密度被激发从金属原子和它的配位球的电子接受配体的一部分。
The state of art of the DFT description of charge-transfer electronic excited states of (mostly) d6transition metal complexes is presented and discussed. A brief theoretical background places DFT amongst quantum-chemical techniques and discusses the approximations involved. The time-dependent DFT (TD-DFT) treatment of electronic transitions is introduced, with emphasis on the challenges presented by long-range charge separation. Various ways how to characterize excited states in chemically relevant terms are discussed. Several detailed case studies demonstrate how DFT describes charge-transfer excited states of ReIor RuIIcarbonyl-diimine complexes and interprets their photophysics and photochemistry. This “tutorial” section is followed by an overview of DFT and TD-DFT applications to electronic spectroscopy and excited-state properties of metal carbonyls, strongly emissive organometallics, RuIIphotosensitizers, luminescent “light-switches” and isonitrile complexes of ReIand RuII. Effects of the computational procedure on the quality of the results and the type of information obtained are emphasized. It follows that the most accurate charge-transfer transition energies and descriptions of excited states of low-valent d6metal complexes are obtained when using hybrid functionals and calculating the molecule in the actual solvent. A rather delocalized picture of charge-transfer states of these complexes emerges, whereby the electron density is excited from the metal atom and part of its coordination sphere to the electron-accepting ligand.