State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
J Am Chem Soc. 2010 Sep 15;132(36):12648-52. doi: 10.1021/ja102887t.
C(78) is one of the most widely investigated higher fullerenes. Among its huge isomer family, only one non-IPR (IPR = isolated pentagon ring) cage, the C(2)-symmetric (#22010)C(78), was previously stabilized by endohedral derivatization. Here we report a new C(1)-symmetric non-IPR hollow isomer, (#23863)C(78), which was captured as (#23863)C(78)Cl(8) and then subjected to a regioselective substitution reaction with benzyl hydroperoxide to form (#23863)C(78)(OOCH(2)C(6)H(5))Cl(7). The structural connectivity of (#23863)C(78), which contains a pair of fused pentagons, was confirmed by single-crystal X-ray diffraction analysis of the (#23863)C(78)(OOCH(2)C(6)H(5))Cl(7) molecule, which shares the same fullerene core with (#23863)C(78)Cl(8); support for the structure is provided by comparable IR measurements and computation. Theoretical studies suggest that the differences in C-Cl bond length, intermediate stability, and steric effects of the involved molecules account for the chemical regioselectivity of the substitution reaction.
C(78) 是研究最广泛的高富勒烯之一。在其庞大的异构体家族中，只有一个非 IP 笼（IP = 孤立五边形环），C(2)-对称 (#22010)C(78)，以前通过包合衍生物稳定。在这里，我们报告了一种新的 C(1)-对称非 IP 空心异构体，(#23863)C(78)，它被捕获为 (#23863)C(78)Cl(8)，然后与苄基过氧化物进行区域选择性取代反应，形成 (#23863)C(78)(OOCH(2)C(6)H(5))Cl(7)。(#23863)C(78)的结构连接性，其中包含一对融合的五边形，通过 (#23863)C(78)(OOCH(2)C(6)H(5))Cl(7)分子的单晶 X 射线衍射分析得到证实，该分子与 (#23863)C(78)Cl(8 共享相同的富勒烯核；结构的支持来自于可比的红外测量和计算。理论研究表明，C-Cl 键长、中间体稳定性和参与分子的空间效应的差异解释了取代反应的化学区域选择性。
