Shen Wangqiang, Yang Le, Li Bo, Jin Peng, Yu Bing, Cong Hailin, Akasaka Takeshi, Lu Xing
School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, P. R. China.
Chem Commun (Camb). 2020 Nov 19;56(92):14357-14360. doi: 10.1039/d0cc06226j.
The chemical properties of a prototypical labile mono-EMF, Y@Cs(6)-C82, have been systematically disclosed for the first time via a Bingel-Hirsch reaction. Three mono-adduct isomers, namely, 2a, 2b and 2c out of 44 possibilities for the Y@Cs(6)-C82 cage have been readily isolated, demonstrating surprisingly high regioselectivity. Crystallographic results of 2b unambiguously confirm its molecular structure with a singly bonded bromomalonate group attached onto the Cs(6)-C82 cage. Further computational results rationalize that the high regioselectivity is a consequence of the localization of high spin density and large frontier molecular orbital distribution on the corresponding carbon atoms stemming from the encapsulation of an yttrium atom into the low-symmetry Cs(6)-C82 cage with three-electron transfer from the metal to the cage.
通过Bingel-Hirsch反应首次系统地揭示了典型的不稳定单金属富勒烯Y@Cs(6)-C82的化学性质。在Y@Cs(6)-C82笼状结构的44种可能异构体中，三种单加成异构体，即2a、2b和2c已很容易分离出来，显示出惊人的高区域选择性。2b的晶体学结果明确证实了其分子结构，即一个单键连接的溴丙二酸酯基团连接在Cs(6)-C82笼状结构上。进一步的计算结果表明，高区域选择性是由于钇原子封装到低对称性的Cs(6)-C82笼状结构中，伴随着三个电子从金属转移到笼状结构，导致相应碳原子上高自旋密度和大前线分子轨道分布的局部化。
