Eu@C72: Computed Comparable Populations of Two Non-IPR Isomers
Zdeněk Slanina,
Filip Uhlík,
Shigeru Nagase,
Takeshi Akasaka,
Ludwik Adamowicz,
Xing Lu
Affiliations
Zdeněk Slanina
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
Filip Uhlík
Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Albertov 6, 128 43 Praha 2, Czech Republic
Shigeru Nagase
Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
Takeshi Akasaka
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
Ludwik Adamowicz
Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041, USA
Xing Lu
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
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.
