Sundararajan Mahesh, Ganyushin Dmitry, Ye Shengfa, Neese Frank
Institut für Physikalische und Theoretische Chemie, Wegelerstr. 12, University of Bonn, D-53115 Bonn, Germany.
Dalton Trans. 2009 Aug 14(30):6021-36. doi: 10.1039/b902743b. Epub 2009 May 21.
A newly developed multireference (MR) ab initio method for the calculation of magnetic circular dichroism (MCD) spectra was calibrated through the calculation of the ground- and excited state properties of seven high-spin (S = 3/2) Co(II) complexes. The MCD spectra were computed by the explicit treatment of spin-orbit coupled (SOC) and spin-spin coupled (SSC) N-electron states. For the complexes studied in this work, we found that the SOC is more important than the SSC for determining the ground state zero field splitting (ZFS). Our computed ZFS parameter D for the [Co(PPh(3))(2)Cl(2)] model complex is -17.6 cm(-1), which is reasonably close to the experimental value of -14.8 cm(-1). Generally, the computed absorption and MCD spectra are in fair agreement with experiment for all investigated complexes. Thus, reliable electronic structure and spectroscopic predictions for medium sized transition metal complexes are feasible on the basis of this methodology. This characterizes the presented method as a promising tool for MCD spectra interpretations of transition metal complexes in a variety of areas of chemistry and biology.
一种新开发的用于计算磁圆二色性（MCD）光谱的多参考（MR）从头算方法，通过计算七种高自旋（S = 3/2）Co（II）配合物的基态和激发态性质进行了校准。MCD光谱通过对自旋 - 轨道耦合（SOC）和自旋 - 自旋耦合（SSC）的N电子态进行显式处理来计算。对于本工作中研究的配合物，我们发现对于确定基态零场分裂（ZFS），SOC比SSC更重要。我们计算的[Co（PPh(3)）(2)Cl(2)]模型配合物的ZFS参数D为-17.6 cm(-1)，这与-14.8 cm(-1)的实验值相当接近。一般来说，对于所有研究的配合物，计算得到的吸收光谱和MCD光谱与实验结果相当吻合。因此，基于这种方法，对中等大小的过渡金属配合物进行可靠的电子结构和光谱预测是可行的。这表明所提出的方法是化学和生物学等多个领域中过渡金属配合物MCD光谱解释的一种有前途的工具。
