Quantum Chemical Insight into La₂C₉₆: Metal Carbide Fullerene La₂C₂@C₉₄ versus Dimetallofullerene La₂@C₉₆

Abstract

A family\nof dilanthanum-containing endohedral metallofullerene La₂C_2<i>n</i> (<i>n</i> = 46–51)\nwas synthesized recently. In the present work, a systematical investigation\non La₂C₉₆ series including the carbide clusterfullerene\nform La₂C₂@C₉₄ and the conventional\ndimetallofullerene form La₂@C₉₆ was implemented\nby density functional theory, combined with statistical mechanics.\nThree 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\nregion of endohedral metallofullerene formation. La₂@D₂(191838)-C₉₆ is the prevailing isomer at low temperature,\nwhile La₂C₂@C_s(153479)-C₉₄ and La₂C₂@C₁(153491)-C₉₄ are the most and second-most abundant isomers at high temperature.\nInterestingly, the highest occupied molecular orbital (HOMO) of La₂C₂@C₁(153491)-C₉₄ is distributed\non one pole of the cage, and the lowest unoccupied molecular orbital\n(LUMO) of this isomer is mainly located on the equator of the cage,\nwhich can facilitate synthesis of regioselective derivatives. This\nwork will provide useful information for further experimental identification\nand application of La₂C₉₆.