Boggiano Andrew C, Niklas Julie E, Bernbeck Maximilian G, La Pierre Henry S
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States.
Nuclear and Radiological Engineering and Medical Physics Program, School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States.
Inorg Chem. 2025 Feb 10;64(5):2489-2495. doi: 10.1021/acs.inorgchem.4c04973. Epub 2025 Jan 26.
While several ligand systems support uranium across a range of oxidation states, spanning more than two oxidation states in a conserved coordination geometry is uncommon among structurally authenticated complexes. Imidophosphorane ligands significantly stabilize high-valent lanthanide and actinide complexes. Here, we report a series of homoleptic uranium imidophosphorane complexes, spanning the +4, +5 and +6 oxidation states in a four-coordinate pseudotetrahedral ligand field. The +6 oxidation state is accessible using a mild ferrocenium oxidant, yielding a rare example of U in a pseudotetrahedral coordination environment. As the formal oxidation state increases, the U-N distances gradually contract, consistent with the Shannon ionic radii of U. Compared to reported complexes, the short U-N distances observed in the U complex are more comparable to dianionic imido ligands than monoanionic amido ligands.
虽然有几种配体体系能在一系列氧化态下稳定铀，但在结构已确定的配合物中，在保守的配位几何结构中跨越两个以上氧化态并不常见。亚氨基磷烷配体能显著稳定高价镧系和锕系配合物。在此，我们报道了一系列纯配体铀亚氨基磷烷配合物，它们在四配位伪四面体配体场中涵盖了 +4、+5 和 +6 氧化态。使用温和的二茂铁氧化剂可得到 +6 氧化态，这是在伪四面体配位环境中铀的一个罕见例子。随着形式氧化态的增加，U-N 距离逐渐缩短，这与铀的香农离子半径一致。与已报道的配合物相比，在铀配合物中观察到的短 U-N 距离与双阴离子亚氨基配体的更相似，而非单阴离子氨基配体的。
