Synthesis, Isolation, and Structural Study of Trifluoromethyl Derivatives of the IPR Isomer of C84 Fullerene, C84(11)(CF3)14,16,18

Abstract

AbstractC84 is the most abundant higher fullerene which is present in the arc‐discharge fullerene soot. Among 24 topologically possible IPR isomers of C84, two major isomers, C84(22) and C84(23), and several minor ones have been identified experimentally. We report the synthesis, isolation, and structure elucidation of trifluoromethyl derivatives of the most abundant minor isomer of C84, C84(11)(CF3)14,16,18. The experimentally determined addition patterns of altogether eight new compounds, four C84(11)(CF3)14, three C84(11)(CF3)16, and one C84(11)(CF3)18, are discussed in terms of the attachments in ribbons of para C6(CF3)2 hexagons and formation of stabilizing substructures of local aromaticity on the C2−C84(11) carbon cage. The general principles of multi addition of bulky CF3 groups are considered which are based on theoretical DFT calculations of formation energies of C84(11)(CF3)n isomers. Thus, trifluoromethylation pathways are now discussed in details for five different isomers of C84.