Zirconium Carbide Clusters Stabilized within Carbon Cages

Identifier:  imarina:9468498

Handle: https://hdl.handle.net/20.500.11797/imarina9468498

Authors:  Shen, Y; Abella, L; Yao, YR; Meng, QY; Luo, RR; Li, B; Wu, ZX; Poblet, JM; Rodriguez-Fortea, A; Chen, N

Abstract:
Zirconium-based endohedral metallofullerenes (EMFs) were first detected in the gas phase in 1992, but their bulk synthesis has remained elusive over the past three decades. Herein, we present the first successful synthesis of Zr-based EMFs, addressing this longstanding challenge in fullerene chemistry. By utilizing an optimized synthesis strategy with zirconium carbide as the metal source, we obtained three Zr-based carbide clusterfullerenes, namely, Zr2C2@D 3h (5)-C78, Zr2C2@I h (7)-C80, and Zr3C2@I h (7)-C80. Single-crystal X-ray diffraction analyses revealed that the Zr2C2 clusters adopt a planar rhombic configuration bridged by a (C equivalent to C)2- unit, while the Zr3C2 cluster exhibits a rare trifoliate geometry with a bridging (C-C)6- unit. The coordination modes in these Zr-based clusters are different from those observed in conventional organozirconium complexes, highlighting the unique coordination environments within fullerene cages. Combined experimental and theoretical studies further reveal the electronic structures of the Zr-based EMFs as (Zr2C2)6+@(C2n )6- (2n = 78, 80) and (Zr3C2)6+@(I h (7)-C80)6-. This breakthrough in the synthesis of Zr-based EMFs not only offers new insights into the mechanisms of arc-discharge reaction and the formation of EMFs but also provides a substantial guideline for the encapsulation of new elements into fullerene cages, establishing a foundation for the design and synthesis of novel EMFs.