谌宁副教授与西班牙罗维拉-威尔吉利大学Josep M. Poblet教授、美国德州大学艾尔帕索分校Luis Echegoyen教授、物理与光电·能源学部冯莱教授合作在J. Am. Chem. Soc. 上发表研究论文

U2@Ih(7)-C80: Crystallographic Characterization of a Long-Sought Dimetallic Actinide Endohedral Fullerene

Xingxing Zhang,Yaofeng Wang,Roser Morales-Martínez§,Jun Zhong,Coen de Graaf§#,Antonio Rodríguez-Fortea§,Josep M. Poblet*§,Luis Echegoyen*,Lai Feng*(冯莱), andNing Chen*(谌宁)

  

Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science,Soochow University,Suzhou,Jiangsu215123,PR China

§Departament de Química Física i Inorgànica,Universitat Rovira i Virgili,c/Marcel·lí Domingo 1,43007Tarragona,Spain

Department of Chemistry,University of Texas at El Paso,500 West University Avenue,El Paso,Texas79968,United States

Soochow Institute for Energy and Materials InnovationS (SIEMIS), College of Physics, Optoelectronics and Energy & Collaborative,Soochow University,Suzhou,Jiangsu215006,PR China

Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM),Soochow University,Suzhou,Jiangsu215123,PR China

#ICREA,Pg Lluis Companys 23,Barcelona08010,Spain

  

J. Am. Chem. Soc.,2018,140(11), 3907--3915

  

The nature of actinide–actinide bonds has attracted considerable attention for a long time, especially since recent theoretical studies suggest that triple and up to quintuple bonds should be possible, but little is known experimentally. Actinide–actinide bonds inside fullerene cages have also been proposed, but their existence has been debated intensively by theoreticians. Despite all the theoretical arguments, critical experimental data for a dimetallic actinide endohedral fullerene have never been obtained. Herein, we report the synthesis and isolation of a dimetallic actinide endohedral metallofullerene (EMF), U2@C80. This compound was fully characterized by mass spectrometry, single crystal X-ray crystallography, UV–vis–NIR spectroscopy, Raman spectroscopy, cyclic voltammetry, and X-ray absorption spectroscopy (XAS). The single crystal X-ray crystallographic analysis unambiguously assigned the molecular structure to U2@Ih(7)-C80. In particular, the crystallographic data revealed that the U–U distance is within the range of 3.46–3.79 Å, which is shorter than the 3.9 Å previously predicted for an elongated weak U–U bond inside the C80cage. The XAS results reveal that the formal charge of the U atoms trapped inside the fullerene cage is +3, which agrees with the computational and crystallographic studies that assign a hexaanionic carbon cage, (Ih-C80)6–. Theoretical studies confirm the presence of a U–U bonding interaction and suggest that the weak U–U bond in U2@Ih(7)-C80is strengthened upon reduction and weakened upon oxidation. The comprehensive characterization of U2@Ih(7)-C80and the overall agreement between the experimental data and theoretical investigations provide experimental proof and deeper understanding for actinide metal–metal bonding interactions inside a fullerene cage.

  

  

链接:https://pubs.acs.org/doi/10.1021/jacs.7b10865