Production and isolation of the isomers of dimetallofulerenes, HoTm@C-82 and Tm-2@C-82

Metallofullerenes encapsulating Ho and Tm atoms were isolated by using the HPLC method with two different columns. Three isomers of HoTm@C-82 and five isomers of Tm-2@C-82 were identified. The UV-VIS-MR absorption spectra of these isomer species were similar to those of the corresponding isomers of Er-2@C-82. This suggests that the cages of HoTm@C-82 and Tm-2@C-82 have the same charge as that of Er-2@C-82 and that Tm takes the trivalent state in HoTm@C-82 and Tm-2@C-82, contrary to the divalent state in Tm@C-82. (C) 200 0 Elsevier Science B.V. All rights reserved.