Poly(perfluoroalkylation) of Metallic Nitride Fullerenes Reveals Addition-Pattern Guidelines: Synthesis and Characterization of a Family of Sc3N@C80(CF3)n (n = 2−16) and Their Radical Anions

A family of highly stable (poly)perfluoroalky-lated metallic nitride cluster fullerenes was prepared in high-temperature reactions and characterized by spectroscopic (MS, 19F NMR, UV−vis/NIR, ESR), structural and electrochemical methods. For two new compounds, Sc3N@C80(CF3)10 and Sc3N@C80(CF3)12, single crystal X-ray structures are determined. Addition pattern guidelines for endohedral fullerene derivatives with bulky functional groups are formulated as a result of experimental (19F NMR spectroscopy and single crystal X-ray diffraction) studies and exhaustive quantum chemical calculations of the structures of Sc3N@C80(CF3)n (n = 2-16). Electrochemical studies revealed that Sc3N@C80(CF3)n derivatives are easier to reduce than Sc3N@C80, the shift of E1/2 potentials ranging from +0.11 V (n = 2) to +0.42 V (n = 10). Stable radical anions of Sc3N@C80(CF3)n were generated in solution and characterized by ESR spectroscopy, revealing their 45Sc hyperfine structure. Facile further functionalizations via cycloaddit...