Electronic Properties and 13C NMR Structural Study of Y3N@C88

In this paper, we report the synthesis, purification, 13C NMR, and other characterization studies of Y3N@C88. The 13C NMR, UV−vis, and chromatographic data suggest an Y3N@C88 having an IPR-allowed cage with D2(35)-C88 symmetry. In earlier density functional theory (DFT) computational and X-ray crystallographic studies, it was reported that lanthanide (A3N)6+ clusters are stabilized in D2(35)-C88 symmetry cages and have reduced HOMO−LUMO gaps relative to other trimetallic nitride endohedral metallofullerene cage systems, for example, A3N@C80. In this paper, we report that the nonlanthanide (Y3N)6+ cluster in the D2(35)-C88 cage exhibits a HOMO−LUMO gap consistent with other lanthanide A3N@C88 molecules based on electrochemical measurements and DFT computational studies. These results suggest that the reduced HOMO−LUMO gap of A3N@C88 systems is a property dominated by the D2(35)-C88 carbon cage and not f-orbital lanthanide electronic metal cluster (A3N)6+ orbital participation.