Electronic Structure of Ru 2 6+ Complexes with Electron-Rich Anilinopyridinate Ligands
Electronic Structure of Ru 2 6+ Complexes with Electron-Rich Anilinopyridinate Ligands
复制标题
富电子苯胺基吡啶配体 Ru 2 6 配合物的电子结构
DOI：
10.1021/acs.inorgchem.1c03346
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发表时间：
2022
影响因子：
4.6
通讯作者：
Berry, John F.
中科院分区：
文献类型：
--
作者：
Roy, Michael D.;Trenerry, Michael J.;Thakuri, Biswash;MacMillan, Samantha N.;Liptak, Matthew D.;Lancaster, Kyle M.;Berry, John F.
合成了富电子苯胺基吡啶（Xap）配体负载的Diruthenium paddlewheel配合物，首次对Ru 26+氧化态的单阳离子[Ru 2（Xap）4Cl]+进行了结构和光谱研究.尽管化合物具有顺磁性，但1H NMR光谱证明对于确定Ru 25+和Ru 26+化合物的异构性具有高度信息性。虽然发现大多数化合物具有极性（4，0）几何形状，所有四个Xap配体都处于相同的取向，但一些合成程序导致（4，0）和（3，1）异构体的混合物，最值得注意的是母体化合物Ru 2（ap）4Cl的情况。这种化合物的异构现象在以前的报告中被忽略了。电化学研究表明，氧化电位可以通过安装给电子基团的配体，增加可达性的Ru 26+氧化态进行调整。通过维斯/近红外吸收光谱和MCD光谱对Ru ~（26+）的电子跃迁进行了深入研究，并利用TD-DFT对电子光谱进行了归属。空δ* 轨道是最显著电子跃迁的主要受体轨道。Ru 25+和Ru 26+的化合物进行了研究，Ru K-边X-射线吸收光谱，然而，上升沿能量是不敏感的氧化还原变化的化合物，由于观察到的宽线形状为4d过渡金属K-边。DFT计算表明，在前线水平的配体轨道的存在下，这表明进一步氧化超过Ru 26+将配体中心，而不是金属中心。
Diruthenium paddlewheel complexes supported by electron-rich anilinopyridinate (Xap) ligands were synthesized in the course of the first in-depth structural and spectroscopic interrogation of monocationic [Ru2(Xap)4Cl]+species in the Ru26+oxidation state. Despite paramagnetism of the compounds,1H NMR spectroscopy proved highly informative for determining the isomerism of the Ru25+and Ru26+compounds. While most compounds are found to have the polar (4,0) geometry, with all four Xap ligands in the same orientation, some synthetic procedures resulted in a mixture of (4,0) and (3,1) isomers, most notably in the case of the parent compound Ru2(ap)4Cl. The isomerism of this compound has been overlooked in previous reports. Electrochemical studies demonstrate that oxidation potentials can be tuned by the installation of electron donating groups to the ligands, increasing accessibility of the Ru26+oxidation state. The resulting Ru26+monocations were found to have the expected (π*)2ground state, and an in-depth study of the electronic transitions by Vis/NIR absorption and MCD spectroscopies with the aid of TD-DFT allowed for the assignment of the electronic spectra. The empty δ* orbital is the major acceptor orbital for the most prominent electronic transitions. Both Ru25+and Ru26+compounds were studied by Ru K-edge X-ray absorption spectroscopy; however, the rising edge energy is insensitive to redox changes in the compounds due to the broad line shape observed for 4d transition metal K-edges. DFT calculations indicate the presence of ligand orbitals at the frontier level, suggesting that further oxidation beyond Ru26+will be ligand-centered rather than metal-centered.