Preferential Encapsulation and Stability of La₃N Cluster in 80 Atom Cages: Experimental Synthesis and Computational Investigation of La₃N@C₇₉

Authors

Steven Stevenson, University of Southern Mississippi
Yan Ling, University of Southern MississippiFollow
Curtis E. Coumbe, University of Southern Mississippi
Mary A. Mackey, University of Southern Mississippi
Bridget S. Confait, University of Southern Mississippi
J. Paige Phillips, University of Southern MississippiFollow
Harry C. Dorn, Virginia Polytechnic Institute and State University
Yong Zhang, University of Southern MississippiFollow

Document Type

Article

Publication Date

12-16-2009

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Abstract

We report the synthesis and electronic stabilization of La₃N@C₇₉N. Unsuccessful efforts to encapsulate bulky La₃N clusters in small C₈₀ cages have been attributed to large ionic radii. The preferred species for La₃N clusters in all-carbon cages is La₃N@C₉₆. A surprising finding is the synthesis of La₃N@C₇₉N, a new metallofullerene present in higher abundance than La₃N@C₉₆. This reduction in cage size from 96 to 80 atoms reflects the significance and role of electronic effects. To understand the geometric and electronic properties of this first metallic nitride azafullerene (M₃N@C₇₉N, M = La), density functional theory (DFT) investigations were performed on a number of isomers. Results indicate a preferred N-substitution at the 665 junction site on the cage in lieu of a 666 substitution. The relative stabilities of different isomers can be well reproduced by using the minimum distance between the metal atom and the nitrogen atom of the cage (R_N′M^min). Long R_N′M^min values indicate distant contacts between six atoms that bear significantly large positive charges: the three metal atoms and the three carbon atoms bonded with the nitrogen atom in the cage, which are favored. These results suggest a dominant electronic effect on the stabilities of metalloazafullerenes. Interestingly, spin densities of the 665 substitution isomers of La₃N@C₇₉N are located predominantly in the metal cluster, while spin densities of the 666 substitution isomers are primarily on the cage.

Publication Title

Journal of the American Chemical Society

Volume

131

Issue

49

First Page

17780

Last Page

17782

Recommended Citation

Stevenson, S., Ling, Y., Coumbe, C., Mackey, M., Confait, B. S., Phillips, J. P., Dorn, H. C., Zhang, Y. (2009). Preferential Encapsulation and Stability of La₃N Cluster in 80 Atom Cages: Experimental Synthesis and Computational Investigation of La₃N@C_{79. Journal of the American Chemical Society, 131(49), 17780-17782.
Available at: https://aquila.usm.edu/fac_pubs/8936}