Slanina Zdeněk, Uhlík Filip, Nagase Shigeru, Akasaka Takeshi, Adamowicz Ludwik, Lu Xing
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Material Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Albertov 6, 128 43 Praha 2, Czech Republic.
Molecules. 2017 Jun 24;22(7):1053. doi: 10.3390/molecules22071053.
Relative concentrations of six isomeric Eu@C 72 -one based on the IPR C 72 cage (i.e., obeying the isolated-pentagon rule, IPR), two cages with a pentagon-pentagon junction (symmetries C 2 and C 2 v ), a cage with one heptagon, a cage with two heptagons, and a cage with two pentagon-pentagon fusions-are DFT computed using the Gibbs energy in a broad temperature interval. It is shown that the two non-IPR isomers with one pentagon-pentagon junction prevail at any relevant temperature and exhibit comparable populations. The IPR-satisfying structure is disfavored by both energy and entropy.
基于IPR C72笼（即遵循孤立五边形规则，IPR）的六种异构体Eu@C72-单的相对浓度，两个具有五边形-五边形连接的笼（对称性C2和C2v），一个具有一个七边形的笼，一个具有两个七边形的笼，以及一个具有两个五边形-五边形融合的笼，使用吉布斯自由能在较宽温度区间内进行密度泛函理论（DFT）计算。结果表明，两种具有一个五边形-五边形连接的非IPR异构体在任何相关温度下都占主导地位，且表现出相当的丰度。满足IPR的结构在能量和熵方面都不利。
