Stabilizing a three-center single-electron metal-metal bond in a fullerene cage

• Published in: Chemical science (Cambridge) Vol. 12; no. 2; pp. 689 - 6895
• Main Authors: Jin, Fei, Xin, Jinpeng, Guan, Runnan, Xie, Xiao-Ming, Chen, Muqing, Zhang, Qianyan, Popov, Alexey A, Xie, Su-Yuan, Yang, Shangfeng
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 02-04-2021; The Royal Society of Chemistry
• Subjects: Charge distribution; Chemistry; Clusters; Configurations; Dysprosium; Electronic structure; Encapsulation; Fullerenes; Metal-metal bonding; Molecular structure; Rare earth elements; Single crystals; Single electrons
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d1sc00965f

Trimetallic carbide clusterfullerenes (TCCFs) encapsulating a quinary M
3
C
2
cluster represent a special family of endohedral fullerenes with an open-shell electronic configuration. Herein, a novel TCCF based on a medium-sized rare earth metal, dysprosium (Dy), is synthesized for the first time. The molecular structure of Dy
3
C
2
@
I
h
(7)-C
80
determined by single crystal X-ray diffraction shows that the encapsulated Dy
3
C
2
cluster adopts a bat ray configuration, in which the acetylide unit C
2
is elevated above the Dy
3
plane by ∼1.66 Å, while Dy-Dy distances are ∼3.4 Å. DFT computational analysis of the electronic structure reveals that the endohedral cluster has an unusual formal charge distribution of (Dy
3
)
8+
(C
2
)
2−
@C
80
6−
and features an unprecedented three-center single-electron Dy-Dy-Dy bond, which has never been reported for lanthanide compounds. Moreover, this electronic structure is different from that of the analogous Sc
3
C
2
@
I
h
(7)-C
80
with a (Sc
3
)
9+
(C
2
)
3−
@C
80
6−
charge distribution and no metal-metal bonding.
A novel trimetallic carbide clusterfullerene, Dy
3
C
2
@
I
h
(7)-C
80
, was successfully synthesized and isolated, and the encapsulated Dy
3
C
2
cluster adopts a bat ray configuration featuring an unprecedented three-center single-electron Dy-Dy-Dy bond.