Theoretical Insights
into Monometallofullerene Th@C<sub>76</sub>: Strong Covalent Interaction
between Thorium and the Carbon Cage
ZhaoPei
ZhaoXiang
EharaMasahiro
2018
Th@C<sub>76</sub> has been studied
by density functional theory combined with statistical mechanics calculations.
The results reveal that Th@<i>T</i><sub><i>d</i></sub>(19151)-C<sub>76</sub> satisfying the isolated pentagon rule
possesses the lowest energy. Nevertheless, considering the enthalpy–entropy
interplay, Th@<i>C</i><sub>1</sub>(17418)-C<sub>76</sub> with one pair of adjacent pentagons is thermodynamically favorable
at elevated temperatures, which is reported for the first time. The
bonding critical points in both isomers were analyzed to disclose
covalent interactions between the inner Th and cages. In addition,
the Wiberg bond orders of M–C bonding in different endohedral
metallofullerenes (EMFs) were investigated to prove stronger covalent
interactions of Th–C in Th-based EMFs.