Determining addition pathways and stable isomers for CF(3) functionalization of endohedral Gd@C(60)

Using density functional theory approaches, we follow the sequential addition of CF(3) functional groups to the surface of the metallic endofullerene species Gd@C(60). The presence of gadolinium in the interior of the cage strongly influences the addition sequence. The calculations are able to successfully identify end points in the addition sequence at Gd@C(60)(CF(3)) (n) , n = 3 and two isomers at n = 5, in predictive agreement with experiment. Inverting the algorithm to determine the most labile groups also identifies the correct positively charged Gd@C60(CF3)4+ isomer, as confirmed by experimental mass spectra. The importance of surface mobility, notably at later stage addition, is discussed.