Supplementary Information
(Synchrotron X-Ray Powder Diffraction on Sc2@C66)
Chun-Ru Wang*, Tsutomu Kai*, Tetsuo Tomiyama*, Takuya Yoshida†,
Yuji Kobayashi†, Eiji Nishibori††, Masaki Takata††, Makoto Sakata††
&
Hisanori Shinohara*
* Department of Chemistry, Nagoya University, Nagoya 464-8602, Japan
e-mail: nori@nano.chem.nagoya-u.ac.jp
†
††
Department of Pharmacology, Osaka University, Osaka 565-0871, Japan
Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
Sc2@C66 powder samples grown from toluene solvent were sealed in a silica glass capillary
(0.3 mm inside diameter).
X-ray powder pattern with good counting statistics was measured by the
synchrotron radiation (SR) X-ray powder experiment with imaging plate (IP) as detectors at SPring-8
BL02B2. The exposure time on IP was 2 hours.
The wavelength of incident X-rays was 0.75 Å. The X-ray powder pattern of Sc2@C66 was
obtained with a 0.02° step up to 20.3° in 2q, which corresponds to 2.0 Å resolution in d-spacing. By
pre-Rietveld analysis of the MEM/Rietveld analysis1-3), the Sc2@C66 crystal structure is determined
as that of space group Pmn21(No.31); a=10.552(2) Å, b=14.198(2) Å, 10.553(1) Å. The Sc-Sc
distance is 2.87(9) Å. The reliable factors of the final Rietveld fitting were Rwp=2.4%. and RI=13.1%.
In the MEM charge densities, the part of Sc dimmer can be seen through the 6-membered
ring. The reliable factors for the structure factors calculated from the final MEM charge density is
5.4% which indicates the present IPR violent cage model are the best possible model in good
accordance with the synchrotron powder diffraction data.
The present crystal involves two toluene solvent molecules per unit cell.
The MEM analysis in all the previous works was done by using the 2 constraint like
as 2 = S[(Fobs-Fmem)2/s2 ]=N where Fobs is observed structure factor, Fmem is the calculated
structure factors from the obtained MEM density, shigma is observed error of data, and N is the total
number of measurements. In the final MEM result
the references.
1-3
2 is always N.
This is mentioned clearly in
The reliable factor of MEM result, R=(|Fbs|-|Fcal|)/Fobs is easy to know the
reliability of the analysis for the general people. As for the final Rietveld fitting, the ratio R wp/Re,
sometimes referred to as the ‘ factor’ or goodness of fit, was 1.5, which is the value indicating an
fairly good quality refinement.
The refined coordinates of the central position of molecules and atom were as
follows.
Atom
x
y
z
B
C66(Center)
0.00000
0.268(2)
-0.041(3)
11.0(7)
SC
0.130(6)
0.362(3)
0.134(2)
23(5)
CH3
0.50000
0.043(2)
0.030(3)
0.40000
C6H5(center)
0.50000
0.040(2)
0.235(3)
0.40000
References
1)
Takata, M. et al.
Confirmation by X-Ray Diffraction of the Endohedral Nature of
the Metallofullerene Y@C82.
2)
Takata, M.et al..
Phys.Rev.Lett.
3)
Takata, M.et al..
Phys.Rev.Lett.
Nature
377, 46-49(1995).
Structure of Endohedral Dimetallofullerene Sc2@C84.
78, 3330 - 3333 (1997).
Triangle Scandium Cluster imprisoned in a Fullerene Cage.
83, 2214 - 2217 (1999).