Crystallographic Evidence for Direct Metal-Metal Bonding in a Stable Open-Shell La2 @Ih -C80 Derivative

Lipiao Bao; Muqing Chen; Changwang Pan; Takahisa Yamaguchi; Tatsuhisa Kato; Marilyn M Olmstead; Alan L Balch; Takeshi Akasaka; Xing Lu

doi:10.1002/anie.201511930

Crystallographic Evidence for Direct Metal-Metal Bonding in a Stable Open-Shell La2 @Ih -C80 Derivative

Angew Chem Int Ed Engl. 2016 Mar 18;55(13):4242-6. doi: 10.1002/anie.201511930. Epub 2016 Feb 25.

Authors

Lipiao Bao¹, Muqing Chen¹, Changwang Pan¹, Takahisa Yamaguchi², Tatsuhisa Kato^{2

3}, Marilyn M Olmstead⁴, Alan L Balch⁴, Takeshi Akasaka^{1

5}, Xing Lu⁶

Affiliations

¹ State Key Laboratory of Materials Processing and Die and Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P.R. China.
² Graduate School of Human and Environmental Sciences, Kyoto University, Kyoto, 606-8501, Japan.
³ Institute for Liberal Arts and Sciences, Kyoto University, Kyoto, 606-8501, Japan.
⁴ Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA.
⁵ Foundation for Advancement of International Science, Tsukuba, 30-0821, Japan.
⁶ State Key Laboratory of Materials Processing and Die and Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P.R. China. lux@hust.edu.cn.

PMID: 26918907
DOI: 10.1002/anie.201511930

Abstract

Endohedral metallofullerenes (EMFs) have novel structures and properties that are closely associated with the internal metallic species. Benzyl radical additions have been previously shown to form closed-shell adducts by attaching an odd number of addends to open-shell EMFs (such as Sc3 C2 @Ih -C80 ) whereas an even number of groups are added to closed-shell EMFs (for example Sc3 N@Ih -C80 ). Herein we report that benzyl radical addition to the closed-shell La2 @Ih -C80 forms a stable, open-shell monoadduct instead of the anticipated closed-shell bisadduct. Single-crystal X-ray diffraction results show the formation of a stable radical species. In this species, the La-La distance is comparable to the theoretical value of a La-La covalent bond and is shorter than reported values for other La2 @Ih -C80 derivatives, providing unambiguous evidence for the formation of direct La-La bond.

Keywords: density functional calculations; endohedral fullerenes; metal-metal bonding; radical reactions; structure elucidation.

Publication types

Research Support, Non-U.S. Gov't