中国科学技术大学杨上峰团队报道了单金属内面体偶氮富勒烯。相关研究成果于2022年11月10日发表在国际顶尖学术期刊《美国化学会杂志》。

由碳笼原子的氮取代衍生的偶氮富勒烯直接修饰了富勒烯的笼骨架、电子和物理化学性质。在1999年，研究人员检测到通过La@C82单加合物破碎形成的气相电离单金属内面体氮杂富勒烯(MEAF) [La@C81N]+，但从未合成过原始MEAF。

该文中，研究人员报道了第一个原始MEAFLa@C81N的合成、分离和表征，应对二十年的挑战。单晶X射线衍射研究表明La@C81N具有具有伪C3v（8）对称性的82原子笼。根据DFT计算，研究人员认为C82笼内的氮取代位点位于远离包封的La原子的六边形/六边形或五边形结处。La@C81N以稳定的单体形式存在，具有封闭壳层电子态，与原始的La@C82开放壳层电子状态有很大不同。

研究人员在合成新型氮杂富勒烯方面的突破为富勒烯的骨架修饰提供了新的见解。

附：英文原文

Title: Monometallic Endohedral Azafullerene

Author: Wenhao Xiang, Xiaole Jiang, Yang-Rong Yao, Jinpeng Xin, Huaimin Jin, Runnan Guan, Qianyan Zhang, Muqing Chen, Su-Yuan Xie, Alexey A. Popov, Shangfeng Yang

Issue&Volume: November 10, 2022

Abstract: Azafullerenes derived from nitrogen substitution of carbon cage atoms render direct modifications of the cage skeleton, electronic, and physicochemical properties of fullerene. Gas-phase ionized monometallic endohedral azafullerene (MEAF) [La@C81N]+ formed via fragmentation of a La@C82 monoadduct was detected in 1999, but the pristine MEAF has never been synthesized. Here, we report the synthesis, isolation, and characterization of the first pristine MEAF La@C81N, tackling the two-decade challenge. Single-crystal X-ray diffraction study reveals that La@C81N has an 82-atom cage with a pseudo C3v(8) symmetry. According to DFT computations, the nitrogen substitution site within the C82 cage is proposed to locate at a hexagon/hexagon/pentagon junction far away from the encapsulated La atom. La@C81N exists in stable monomer form with a closed-shell electronic state, which is drastically different from the open-shell electronic state of the original La@C82. Our breakthrough in synthesizing a new type of azafullerene offers a new insight into the skeletal modification of fullerenes.

DOI: 10.1021/jacs.2c08679

Source: https://pubs.acs.org/doi/10.1021/jacs.2c08679