Chemistry Reference
In-Depth Information
Fig. 4.8
Representation of the Sc
3
N, Lu
3
N, Y
3
N, La
2
,Y
3
,Sc
3
C
2
,Sc
4
C
2
,Sc
3
CH, Sc
3
NC, Sc
4
O
2
,
and Sc
4
O
3
metal cluster structures adopted inside the fullerene cage
When
I
h
-C
80
EMFs are considered, our results show that the encapsulation of
metal clusters inside the cage decreases its reactivity; there is a great increase in
Gibbs reaction barriers and a decrease in Gibbs reaction energies. Here, we report
a brief description of the reactivity and regioselectivity trends of all EMF families
considered in this study:
TNT Clusters (Sc
3
N, Lu
3
N, Y
3
N)
Those systems that present a large HOMO- LUMO
gap and a high charge transfer between the metallic cluster and the cage (see Table
4.2
)
exhibit a low reactivity (i.e. high activation barriers). The regioselectivity of the
cycloaddition reaction depends strongly on the volume of the inner TNT and the
related fullerene deformation energy. The larger the TNT (
or the more deformed
the fullerene cage
), the smaller the energy difference between [6, 6] and [5, 6]
additions, and the less regioselective the reaction. The preference for the [6, 6]
addition increases for those systems that present a larger volume of the metal cluster
and fullerene distortion energy.
