Towards Relative Populations of Non-Isomeric Metallofullerenes: La@C-76(T-d) vs. La-2@C-76(C-S, 17490)
Abstract
Recently, a new member of the lanthanum-containing metallofullerene family has been isolated and its structure determined from X-ray crystallographic analysis, namely La-2@C-76(C-s, 17490), even with two pairs of connected pentagons, hence violating the isolated-pentagon rule (IPR). In order to explain the interesting observation, a computational treatment is suggested for evaluations of the relative populations of nonisomeric metallofullerenes.
As a comparative reference structure, the most stable La@C-76 isomer is selected - the IPR-C-76(T-d)-cage based endohedral La@C-76(T-d). In the relevant temperature region, the La-2@C-76(Cs, 17490) species should be considerably more populated compared to La@C-76(T-d).
The new computational stability treatment is applicable to a wider spectrum of nonisomeric metallofullerenes.