Lewis Acid-Base Adducts of Sc2C2@C3v(8)-C82/N-Heterocyclic Carbene: Toward Isomerically Pure Metallofullerene Derivatives

Lipiao Bao; Muqing Chen; Wangqiang Shen; Le Yang; Peng Jin; Xing Lu

doi:10.1021/acs.inorgchem.7b02578

Lewis Acid-Base Adducts of Sc₂C₂@C_3v(8)-C₈₂/N-Heterocyclic Carbene: Toward Isomerically Pure Metallofullerene Derivatives

Inorg Chem. 2017 Dec 18;56(24):14747-14750. doi: 10.1021/acs.inorgchem.7b02578. Epub 2017 Dec 6.

Authors

Lipiao Bao¹, Muqing Chen¹, Wangqiang Shen¹, Le Yang², Peng Jin², Xing Lu¹

Affiliations

¹ State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , 1037 Luoyu Road, Wuhan 430074, China.
² School of Materials Science and Engineering, Hebei University of Technology , Tianjin 300130, China.

PMID: 29210578
DOI: 10.1021/acs.inorgchem.7b02578

Abstract

The addition of a bulky N-heterocyclic carbene (NHC) to Sc₂C₂@C_3v(8)-C₈₂ affords two monoadducts (2a and 2b) quantitatively and regioselectively, representing the first examples of Lewis acid-base pairs of metal carbide cluster fullerenes. 2b is likely a kinetically favorable labile product that cannot be isolated from the solution. The crystallographic results of 2a unambiguously demonstrate that one polarized C-C single bond is formed between the normal carbene site C2N of the NHC and a specific [5,6,6]-carbon atom out of 17 types of nonequivalent cage carbon atoms of Sc₂C₂@C_3v(8)-C₈₂. Theoretical calculations demonstrate that the high regioselectivity, the unexpected addition pattern, and the quantitative formation of monoadducts are synergistic results from the cage geometry and electron distribution on the cage.