Mapping the Metal Positions inside Spherical C-80 Cages: Crystallographic and Theoretical Studies of Ce-2@D-5h-C-80 and Ce-2@I-h-C-80

作者：Feng, Lai^*; Suzuki, Mitsuaki; Mizorogi, Naomi; Lu, Xing; Yamada, Michio; Akasaka, Takeshi; Nagase, Shigeru

来源：Chemistry - A European Journal, 2013, 19(3): 988-993.

DOI：10.1002/chem.201202341

• crystal engineering
• density functional calculations
• fullerenes
• host-guest systems
• X-ray diffraction

The dynamic positions of the dimetallic cluster inside the mid-sized spherical cages of C80C82 have been seldom studied, despite the high abundance of M2@C2n (2n=80, 82) species among various endohedral metallofullerenes. Herein, using crystallographic methods, we first unambiguously map the metal positions for both Ce2@D5h-C80 and Ce2@Ih-C80, showing how the symmetry or geometrical change in cage structure can influence the motional behavior of the cluster. Inside the D5h cage, the primary cerium sites have been identified along a cage belt of the contiguous hexagons, which suggests the significant influence of such a cage motif on endohedral cluster motion. Further analysis revealed a distorted D5h cage owing to the punch-out effect of cerium atoms. The consequence is the presence of two localized electrostatic potential minima inside the cage of (D5h-C80)6-, thus reflecting the primary ionic ceriumcage interaction. In contrast, a different motional behavior of Ce2 cluster was observed inside the Ih cage. With the major cerium sites, the molecule of Ce2@Ih-C80 presented an approximate D2h configuration. With the combined theoretical study, we propose that the additional unidentified influence of NiII(OEP) (OEP=octaethylporphyrin) might be also relevant for the location of cerium sites inside the Ih cage.

• 出版日期2013-1
• 单位苏州大学