Polarizability Effects Dominate the Chromatographic Retention Behavior of Spheroidal and Elipsoidal Metallofullerene Nanospheres

Abstract

The chromatographic retention behavior of spherical and elipsodial metallofullerenes provides a unique class for studying subtle intermolecular dispersive (London effect) and inductive (Debye effect) solution-state/solid-phase interactions. The known trimetallic nitride endohedral metallofullerene A3N@C80 isomers are nearly spherical A3N@C80-Ih and ellipsoidal A3N@C80-D5h. These metallofullerene isomers are readily available with group IIIB and lanthanide trimetallic nitride clusters (A3N)6+. In the current study, chromatographic HPLC retention behavior is monitored for two different HPLC stationary phases, pentabromobenzyl and pyrenylethyl and augmented by density functional theory computational results. Although dipole moments, lanthanide contraction, and charge transfer from the internal cluster (A3N)6+ are important factors controlling chromatographic retention, our results suggest that the fullerene cage polarizability is the dominant factor controlling chromatographic separation of A3N@C80-Ih and el...