Isolation, Spectroscopic Characterization and Study of Island Formation of Two Isomers of the Metallofullerene Nd@C{sub}82

摘要

Two types of the metallofullerene Nd@C{sub}82 have been isolated and characterized. HPLC was used to isolate Nd@C{sub}82(I, II). The two isomers were characterized by mass spectrometry and UV-Vis-NIR absorption spectroscopy. Nd@C{sub}82(I) was found to be similar in structure to the main isomer of other lanthanofullerenes such as La@C{sub}82. We assign Nd@C{sub}82(I) to have a C{sub}(2v) cage symmetry. Nd@C{sub}82(II) showed a markedly different UV-Vis-NIR absorption spectrum to Nd@C{sub}82(I). Its spectrum is in good agreement with that of the minor isomer of metallofullerenes such as Pr@C{sub}82. We therefore assign Nd@C{sub}82(II) to have a C{sub}s cage symmetry. In contrast to other metallofullerenes, both isomers appear to be equally abundant. Their molecular orbital structures have been studied by a combination of scanning tunnelling microscopy (STM) and density functional theory (DFT). Matching filled and empty-states STM images to DFT calculations allowed us to distinguish directly between the two isomers on a substrate.