Uyeda Christopher, Peters Jonas C
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
Chem Sci. 2013;4(1):157-163. doi: 10.1039/C2SC21231E.
Heterobimetallic NiZn complexes featuring metal centers in distinct coordination environments have been synthesized using diimine-dioxime ligands as binucleating scaffolds. A tetramethylfuran-containing ligand derivative enables a stable one-electron-reduced = 1/2 species to be accessed using CpCo as a chemical reductant. The resulting pseudo-square planar complex exhibits spectroscopic and crystallographic characteristics of a ligand-centered radical bound to a Ni(II) center. Upon coordination of a π-acidic ligand such as PPh, however, a five-coordinate Ni(I) metalloradical is formed. The electronic structures of these reduced species provide insight into the subtle effects of ligand structure on the potential and reversibility of the Ni couple for complexes of redox-active tetraazamacrocycles.
使用二亚胺二肟配体作为双核支架，合成了具有处于不同配位环境的金属中心的异双金属镍锌配合物。一种含四甲基呋喃的配体衍生物，能使用CpCo作为化学还原剂得到稳定的单电子还原的S = 1/2物种。所得的准方形平面配合物表现出与结合到Ni(II)中心的配体中心自由基相关的光谱和晶体学特征。然而，在诸如PPh₃这样的π酸性配体配位后，会形成五配位的Ni(I)金属自由基。这些还原物种的电子结构为理解配体结构对氧化还原活性四氮杂大环配合物中Ni电对的电势和可逆性的微妙影响提供了思路。
