DFT prediction of chromatographic retention behavior for a trimetallic nitride metallofullerene series

The high pressure liquid chromatography (HPLC) retention behavior of fullerenes and metallofullerenes provides a convenient system for studying the intermolecular interactions between conjugated spheroidal π systems and stationary chromatographic phases. Previous studies have established in the absence of significant dipole moments, a linear relationship exists between chromatographic HPLC retention times and the polarizability of fullerenes and endohedral metallofullerenes (EMFs). Previous studies have shown that density functional theory (DFT) can accurately predict the polarizability and dipole moments of fullerenes and EMFs. In the current study, we extend this approach to predict the chromatographic retention behavior of the yttrium and terbium trimetallic nitride metallofullerene series Y3N@C2n (n = 39-44) and Tb3N@C2n (n = 40-44). The results of this study demonstrate that the chromatographic retention behavior of the EMF series can be predicted even for systems that violate the isolated pentagon rule (IPR) with significant dipole moments and significant differences in the symmetry of the fullerene cage. The results of this study can be readily extended to predict the dominate factors for the interactions between other fullerene and metallofullerene homologous series.