Chemical understanding of carbide cluster metallofullerenes: a case study on Sc2C2@C2v(5)-C80 with complete X-ray crystallographic characterizations.
Little is known about the chemical properties of carbide cluster metallofullerenes (CCMFs). Here we report the photochemical reaction of a newly assigned CCMF Sc(2)C(2)@C(2v)(5)-C(80) with 2-adamantane-2,3-[3H]-diazirine (AdN(2), 1), which provides a carbene reagent under irradiation. Five monoadduct isomers (2a-2e), with respective abundances of 20%, 40%, 25%, 5%, and 10%, were isolated and characterized with a combination of experimental techniques including unambiguous single-crystal X-ray crystallography. Results show that the two Sc atoms of the bent Sc(2)C(2) cluster tend to move in most cases, whereas the C(2)-unit is almost fixed. Accordingly, it is difficult to explain the addition patterns by considering the strain and charge density on the cage with a fixed cluster, and thus a moving cluster may account for the addition patterns. These results show that the situation of CCMFs is more complicated than those in other metallofullerenes. Furthermore, a thermal isomerization process from 2b to 2c was observed, confirming that the most abundant isomer 2b is a kinetically favored adduct. Finally, it is revealed that the electronic and electrochemical properties of pristine Sc(2)C(2)@C(2v)(5)-C(80) have been markedly altered by exohedral modification.
Life Science Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
Hiroki
H
Kurihara
Xing
X
Lu
Yuko
Y
Iiduka
Hidefumi
H
Nikawa
Naomi
N
Mizorogi
Zdenek
Z
Slanina
Takahiro
T
Tsuchiya
Shigeru
S
Nagase
Takeshi
T
Akasaka