A diuranium carbide cluster stabilized inside a C80 fullerene cage
Xingxing Zhang1 , Wanlu Li2, Lai Feng3, Xin Chen2, Andreas Hansen4, Stefan Grimme4, Skye Fortier5, Dumitru-Claudiu Sergentu6, Thomas J. Duignan6, Jochen Autschbach 6, Shuao Wang7, Yaofeng Wang1 , Giorgios Velkos8, Alexey A. Popov 8, Nabi Aghdassi9, Steffen Duhm 9, Xiaohong Li1 , Jun Li2, *, Luis Echegoyen4, *, W.H.Eugen Schwarz 2,10 & Ning Chen1, *（谌宁）
1 Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, China.
2Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing 100084, China.
3 Soochow Institute for Energy and Materials InnovationS (SIEMIS), College of Physics, Optoelectronics and Energy & Collaborative, Soochow University, Suzhou, Jiangsu 215006, China.
4 Mulliken Center for Theoretical Chemistry, Universität Bonn, 53115 Bonn, Germany.
5Department of Chemistry, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA.
6Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
7 School of Radiological and Interdisciplinary Sciences & Collaborative Innovation Center of Radiation Medicine of Jiangsu, Higher Education Institutions, Soochow University, Suzhou, Jiangsu 215123, China. 8Nanoscale Chemistry, Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany.
9 Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123, China.
10 Physikalische und Theoretische Chemie, Universität Siegen, 57068 Siegen, Germany.
These authors contributed equally: Xingxing Zhang, Wan-lu Li, Lai Feng.
NATURE COMMUNICATIONS ,2018, 9:2753
Unsupported non-bridged uranium–carbon double bonds have long been sought after in actinide chemistry as fundamental synthetic targets in the study of actinide-ligand multiple bonding. Here we report that, utilizing Ih(7)-C80 fullerenes as nanocontainers, a diuranium carbide cluster, U=C=U, has been encapsulated and stabilized in the form of UCU@Ih(7)- C80. This endohedral fullerene was prepared utilizing the Krätschmer–Huffman arc discharge method, and was then co-crystallized with nickel(II) octaethylporphyrin (NiII-OEP) to produce UCU@Ih(7)-C80·[NiII-OEP] as single crystals. X-ray diffraction analysis reveals a cage-stabilized, carbide-bridged, bent UCU cluster with unexpectedly short uranium–carbon distances (2.03 Å) indicative of covalent U=C double-bond character. The quantum-chemical results suggest that both U atoms in the UCU unit have formal oxidation state of +5. The structural features of UCU@Ih(7)-C80 and the covalent nature of the U(f1 )=C double bonds were further affirmed through various spectroscopic and theoretical analyses