UCN@Cs(6)‑C82: An Encapsulated Triangular UCN Cluster with Ambiguous U Oxidation State [U(III) versus U(I)]
Qingyu Meng1,∥, Laura Abella2,∥, Wei Yang1,∥, Yang-Rong Yao2, Xinye Liu1, Jiaxin Zhuang1, Xiaomeng Li1, Luis Echegoyen2, Jochen Autschbach2,*, and Ning Chen1,*（谌宁）
1 College of Chemistry, Chemical Engineering and Materials Science, and State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, Jiangsu 215123, P. R. China
2 Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
∥Q.M., L.A., and W.Y. contributed equally to this work.
J. Am. Chem. Soc.2021, 143, 16226--16234
Understanding the chemical behavior of actinide elements is essential for the effective management and use of actinide materials. In this study, we report an unprecedented η2 (side-on) coordination of U by a cyanide in a UCN cluster, which was stabilized inside a C82 fullerene cage. UCN@Cs(6)-C82 was successfully synthesized and fully characterized by mass spectrometry, single crystal X-ray crystallography, cyclic voltammetry, spectroscopy, and theoretical calculations. The bonding analysis demonstrates significant donation bonding between CN− and uranium, and covalent interactions between uranium and the carbon cage. These effects correlate with an observed elongated cyanide C−N bond, resulting in a rare case where the oxidation state of uranium shows ambiguity between U(III) and U(I). The discovery of this unprecedented triangular configuration of the uranium cyanide cluster provides a new insight in coordination chemistry and highlights the large variety of bonding situations that uranium can have.
链接：//pubs.acs.org/doi/abs/10.1021/jacs.1c07519
