Fluorinated fullerenes: Synthesis and characterization

Abstract

AbstractThe existence of the fully fluorinated fullerene, C60F60, is still subject to controversy. Mass spectrometric evidence shows that it exists, albeit in trace amounts five orders of magnitude in concentration below the most abundant C60F40‐42. Generally, mixtures of C60Fn are obtained where n ranges from 30 to 52, depending on fluorinating conditions. The species with n = 36 is particularly stable. Attempts to increase n by use of the strongly fluorinating halogen fluorides, ClF3 or BrF5, have led to products C60FXXyOz (X = Br or Cl), where the origin of the oxygen is probably hydrolysis during analysis. Fluorinated C60 crystallizes as a mixture of hexagonal close packed (40%) and face‐centered cubic (60%) phases. X‐ray analysis yields an average C‐F bond length of 1.49A. Fluorination of C70 leads to mixtures with maximum average stoichiometries of C70F52.