New M₃N@C_2<i>n</i> Endohedral Metallofullerene Families (M=Nd, Pr, Ce; <i>n</i>=40–53): Expanding the Preferential Templating of the C₈₈ Cage and Approaching the C₉₆ Cage

Abstract

Abstract Three new families of trimetallic nitride template endohedral metallofullerenes (TNT EMFs), based on cerium, praseodymium, and neodymium clusters, were synthesized by vaporizing packed graphite rods in a conventional Krätschmer–Huffman arc reactor. Each of these families of metallofullerenes was identified and characterized by mass spectroscopy, HPLC, UV/Vis‐NIR spectroscopy, and cyclic voltammetry. The mass spectra and HPLC chromatograms show that these larger metallic clusters are preferentially encapsulated by a C 88 cage. When the size of the cluster is increased, the C 96 cage is progressively favored over the predominant C 88 cage. It is also observed that the smaller cages (C 80 –C 86 ) almost disappear on going from neodymium to cerium endohedral metallofullerenes. The UV/Vis‐NIR spectra and cyclic voltammograms confirm the low HOMO–LUMO gap and reversible electrochemistry of these M 3 N@C 88 metallofullerenes.