Mono-, Di- and Trierbium Endohedral Metallofullerenes: Production, Separation, Isolation, and Spectroscopic Study

The first successful production and chromatographic isolation of erbium endohedral metallofullerenes are reported. A series of 21 different erbium endohedral metallofullerenes, having one, two, and three erbium metal atoms encapsulated in a range of higher fullerene cages, has been separated and isolated. All these newly synthesized metallofullerenes are characterized by LD-TOF mass spectrometry and UV−vis−NIR absorption spectroscopy. Their possible molecular symmetry, HOMO−LUMO band gap, and electronic structure are discussed in terms of their absorption spectra and high-performance liquid chromatography (HPLC) elution time. Their separation and isolation procedure by multistage HPLC is also discussed in detail.