Quantum Chemical Insight into La₂C₉₆: Metal Carbide Fullerene La₂C₂@C₉₄versus Dimetallofullerene La₂@C₉₆

Abstract

A family of dilanthanum-containing endohedral metallofullerene La₂C_2n (n = 46-51) was synthesized recently. In the present work, a systematical investigation on La₂C₉₆ series including the carbide clusterfullerene form La₂C₂@C₉₄ and the conventional dimetallofullerene form La₂@C₉₆ was implemented by density functional theory, combined with statistical mechanics. Three isomers, i.e., La₂@D₂(191838)-C₉₆, La₂C₂@C_s(153479)-C₉₄, and La₂C₂@C₁(153491)-C₉₄ were disclosed to be thermodynamically stable at the temperature region of endohedral metallofullerene formation. La₂@D₂(191838)-C₉₆ is the prevailing isomer at low temperature, while La₂C₂@C_s(153479)-C₉₄ and La₂C₂@C₁(153491)-C₉₄ are the most and second-most abundant isomers at high temperature. Interestingly, the highest occupied molecular orbital (HOMO) of La₂C₂@C₁(153491)-C₉₄ is distributed on one pole of the cage, and the lowest unoccupied molecular orbital (LUMO) of this isomer is mainly located on the equator of the cage, which can facilitate synthesis of regioselective derivatives. This work will provide useful information for further experimental identification and application of La₂C₉₆.