Density functional calculation of the electronic circular dichroism spectra of the transition metal complexes [M(phen)3]2+ (M = Fe, Ru, Os)
Density functional calculation of the electronic circular dichroism spectra of the transition metal complexes [M(phen)3]2+ (M = Fe, Ru, Os)
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DOI：
10.1021/jp0444363
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发表时间：
2005-06-02
影响因子：
2.9
通讯作者：
Autschbach, J
中科院分区：
文献类型：
--
作者：
Le Guennic, B;Hieringer, W;Autschbach, J
采用瞬态密度泛函理论，通过计算研究了三二齿金属配合物 Lambda-[M(phen)(3)](2+)（其中 M = Fe、Ru、Os 和 phen = 1,10-tris-菲咯啉）的圆二色光谱。 Ru 和 Os 的实验光谱与实验光谱吻合良好。详细分析了 Lambda-[Os(phen)(3)](2+) 光谱。它显示了相对论如何影响红移 CD 带，其中 Os 5d 轨道在很大程度上参与激发。此外，金属在配体pi→pi*激子CD中的参与被确定为大约10%。尽管溶剂效应可以对单个跃迁和旋转强度产生显着影响，但它们被证明对所得模拟圆二色光谱的总体影响非常小。对于 Lambda-[Fe(phen)(3)](2+)，结果显示对所应用的混合和非混合密度泛函的选择以及基于此的优化几何结构相当敏感。特别是，Lambda-[Fe(phen)(3)](2+) CD 光谱的低能部分（高达 33 x 10(3) cm(-1)）的符号图案很难再现。泛函和几何的某些组合与实验具有良好的一致性，但无法根据现有结果设计出“最佳”方法。研究了由于泛函和交换相关核的缺陷而导致 Lambda-[Fe(phen)(3)](2+) 谱中可能的误差来源。
The circular dichroism spectra of the tris-bidentate metal complexes Lambda-[M(phen)(3)](2+), with M = Fe, Ru, Os and phen = 1,10-tris-phenanthroline, are investigated computationally, employing time-dependent density functional theory. Good agreement with experimental spectra is obtained for Ru and Os. The Lambda-[Os(phen)(3)](2+) spectrum is analyzed in detail. It is shown how relativistic effects red shift CD bands where the Os 5d-orbital participates to a large extent in the excitations. Further, the participation of the metal in the ligand pi -> pi* exciton CD is determined to be of the order of 10%. Though solvent effects can have a noticeable effect on individual transitions and rotatory strengths, they are demonstrated to have only a very small overall effect on the resulting simulated CD spectra. For Lambda-[Fe(phen)(3)](2+), the results are shown to be rather sensitive to the choice of the applied hybrid and nonhybrid density functionals, and the optimized geometries based thereupon. In particular, the sign pattern of the lower-energy part (up to 33 x 10(3) cm(-1)) of the Lambda-[Fe(phen)(3)](2+) CD spectrum is difficult to reproduce. Some combinations of functionals and geometries yield good agreement with experiment, but no "best" approach can be devised based on the available results. Possible sources of errors in the spectrum of Lambda-[Fe(phen)(3)](2+) due to deficiencies in the functionals and the exchange-correlation kernels are investigated.